// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/printing/renderer/print_web_view_helper.h"

#include <stddef.h>
#include <stdint.h>

#include <algorithm>
#include <string>
#include <utility>

#include "base/auto_reset.h"
#include "base/json/json_writer.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/process/process_handle.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_task_runner_handle.h"
#include "build/build_config.h"
#include "components/printing/common/print_messages.h"
#include "content/public/common/web_preferences.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_thread.h"
#include "content/public/renderer/render_view.h"
#include "grit/components_resources.h"
#include "net/base/escape.h"
#include "printing/features/features.h"
#include "printing/metafile_skia_wrapper.h"
#include "printing/pdf_metafile_skia.h"
#include "printing/units.h"
#include "third_party/WebKit/public/platform/WebDoubleSize.h"
#include "third_party/WebKit/public/platform/WebSize.h"
#include "third_party/WebKit/public/platform/WebURLRequest.h"
#include "third_party/WebKit/public/web/WebConsoleMessage.h"
#include "third_party/WebKit/public/web/WebDocument.h"
#include "third_party/WebKit/public/web/WebElement.h"
#include "third_party/WebKit/public/web/WebFrameClient.h"
#include "third_party/WebKit/public/web/WebFrameOwnerProperties.h"
#include "third_party/WebKit/public/web/WebFrameWidget.h"
#include "third_party/WebKit/public/web/WebLocalFrame.h"
#include "third_party/WebKit/public/web/WebPlugin.h"
#include "third_party/WebKit/public/web/WebPluginDocument.h"
#include "third_party/WebKit/public/web/WebPrintParams.h"
#include "third_party/WebKit/public/web/WebPrintPresetOptions.h"
#include "third_party/WebKit/public/web/WebSandboxFlags.h"
#include "third_party/WebKit/public/web/WebScriptSource.h"
#include "third_party/WebKit/public/web/WebSettings.h"
#include "third_party/WebKit/public/web/WebView.h"
#include "third_party/WebKit/public/web/WebViewClient.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "ui/base/resource/resource_bundle.h"

using content::WebPreferences;

namespace printing {

namespace {

#define STATIC_ASSERT_ENUM(a, b)                            \
  static_assert(static_cast<int>(a) == static_cast<int>(b), \
                "mismatching enums: " #a)

// Check blink and printing enums are kept in sync.
STATIC_ASSERT_ENUM(blink::WebUnknownDuplexMode, UNKNOWN_DUPLEX_MODE);
STATIC_ASSERT_ENUM(blink::WebSimplex, SIMPLEX);
STATIC_ASSERT_ENUM(blink::WebLongEdge, LONG_EDGE);
STATIC_ASSERT_ENUM(blink::WebShortEdge, SHORT_EDGE);

enum PrintPreviewHelperEvents {
  PREVIEW_EVENT_REQUESTED,
  PREVIEW_EVENT_CACHE_HIT,  // Unused
  PREVIEW_EVENT_CREATE_DOCUMENT,
  PREVIEW_EVENT_NEW_SETTINGS,  // Unused
  PREVIEW_EVENT_MAX,
};

const double kMinDpi = 1.0;

// Also set in third_party/WebKit/Source/core/page/PrintContext.cpp
const float kPrintingMinimumShrinkFactor = 1.333f;

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
bool g_is_preview_enabled = true;

const char kPageLoadScriptFormat[] =
    "document.open(); document.write(%s); document.close();";

const char kPageSetupScriptFormat[] = "setup(%s);";

void ExecuteScript(blink::WebFrame* frame,
                   const char* script_format,
                   const base::Value& parameters) {
  std::string json;
  base::JSONWriter::Write(parameters, &json);
  std::string script = base::StringPrintf(script_format, json.c_str());
  frame->executeScript(blink::WebString(base::UTF8ToUTF16(script)));
}
#else
bool g_is_preview_enabled = false;
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

int GetDPI(const PrintMsg_Print_Params* print_params) {
#if defined(OS_MACOSX)
  // On the Mac, the printable area is in points, don't do any scaling based
  // on dpi.
  return kPointsPerInch;
#else
  return static_cast<int>(print_params->dpi);
#endif  // defined(OS_MACOSX)
}

bool PrintMsg_Print_Params_IsValid(const PrintMsg_Print_Params& params) {
  return !params.content_size.IsEmpty() && !params.page_size.IsEmpty() &&
         !params.printable_area.IsEmpty() && params.document_cookie &&
         params.desired_dpi && params.dpi && params.margin_top >= 0 &&
         params.margin_left >= 0 && params.dpi > kMinDpi &&
         params.document_cookie != 0;
}

// Helper function to check for fit to page
bool IsWebPrintScalingOptionFitToPage(const PrintMsg_Print_Params& params) {
  return params.print_scaling_option ==
         blink::WebPrintScalingOptionFitToPrintableArea;
}

PrintMsg_Print_Params GetCssPrintParams(
    blink::WebLocalFrame* frame,
    int page_index,
    const PrintMsg_Print_Params& page_params) {
  PrintMsg_Print_Params page_css_params = page_params;
  int dpi = GetDPI(&page_params);

  blink::WebDoubleSize page_size_in_pixels(
      ConvertUnitDouble(page_params.page_size.width(), dpi, kPixelsPerInch),
      ConvertUnitDouble(page_params.page_size.height(), dpi, kPixelsPerInch));
  int margin_top_in_pixels =
      ConvertUnit(page_params.margin_top, dpi, kPixelsPerInch);
  int margin_right_in_pixels = ConvertUnit(
      page_params.page_size.width() -
      page_params.content_size.width() - page_params.margin_left,
      dpi, kPixelsPerInch);
  int margin_bottom_in_pixels = ConvertUnit(
      page_params.page_size.height() -
      page_params.content_size.height() - page_params.margin_top,
      dpi, kPixelsPerInch);
  int margin_left_in_pixels = ConvertUnit(
      page_params.margin_left,
      dpi, kPixelsPerInch);

  if (frame) {
    frame->pageSizeAndMarginsInPixels(page_index,
                                      page_size_in_pixels,
                                      margin_top_in_pixels,
                                      margin_right_in_pixels,
                                      margin_bottom_in_pixels,
                                      margin_left_in_pixels);
  }

  double new_content_width = page_size_in_pixels.width() -
                          margin_left_in_pixels - margin_right_in_pixels;
  double new_content_height = page_size_in_pixels.height() -
                           margin_top_in_pixels - margin_bottom_in_pixels;

  // Invalid page size and/or margins. We just use the default setting.
  if (new_content_width < 1 || new_content_height < 1) {
    CHECK(frame != NULL);
    page_css_params = GetCssPrintParams(NULL, page_index, page_params);
    return page_css_params;
  }

  page_css_params.page_size =
      gfx::Size(ConvertUnit(page_size_in_pixels.width(), kPixelsPerInch, dpi),
                ConvertUnit(page_size_in_pixels.height(), kPixelsPerInch, dpi));
  page_css_params.content_size =
      gfx::Size(ConvertUnit(new_content_width, kPixelsPerInch, dpi),
              ConvertUnit(new_content_height, kPixelsPerInch, dpi));

  page_css_params.margin_top =
      ConvertUnit(margin_top_in_pixels, kPixelsPerInch, dpi);
  page_css_params.margin_left =
      ConvertUnit(margin_left_in_pixels, kPixelsPerInch, dpi);
  return page_css_params;
}

double FitPrintParamsToPage(const PrintMsg_Print_Params& page_params,
                            PrintMsg_Print_Params* params_to_fit) {
  double content_width =
      static_cast<double>(params_to_fit->content_size.width());
  double content_height =
      static_cast<double>(params_to_fit->content_size.height());
  int default_page_size_height = page_params.page_size.height();
  int default_page_size_width = page_params.page_size.width();
  int css_page_size_height = params_to_fit->page_size.height();
  int css_page_size_width = params_to_fit->page_size.width();

  double scale_factor = 1.0f;
  if (page_params.page_size == params_to_fit->page_size)
    return scale_factor;

  if (default_page_size_width < css_page_size_width ||
      default_page_size_height < css_page_size_height) {
    double ratio_width =
        static_cast<double>(default_page_size_width) / css_page_size_width;
    double ratio_height =
        static_cast<double>(default_page_size_height) / css_page_size_height;
    scale_factor = ratio_width < ratio_height ? ratio_width : ratio_height;
    content_width *= scale_factor;
    content_height *= scale_factor;
  }
  params_to_fit->margin_top = static_cast<int>(
      (default_page_size_height - css_page_size_height * scale_factor) / 2 +
      (params_to_fit->margin_top * scale_factor));
  params_to_fit->margin_left = static_cast<int>(
      (default_page_size_width - css_page_size_width * scale_factor) / 2 +
      (params_to_fit->margin_left * scale_factor));
  params_to_fit->content_size = gfx::Size(static_cast<int>(content_width),
                                          static_cast<int>(content_height));
  params_to_fit->page_size = page_params.page_size;
  return scale_factor;
}

void CalculatePageLayoutFromPrintParams(
    const PrintMsg_Print_Params& params,
    double scale_factor,
    PageSizeMargins* page_layout_in_points) {
  bool fit_to_page = IsWebPrintScalingOptionFitToPage(params);
  int dpi = GetDPI(&params);
  int content_width = params.content_size.width();
  int content_height = params.content_size.height();
  // Scale the content to its normal size for purpose of computing page layout.
  // Otherwise we will get negative margins.
  if (scale_factor >= PrintWebViewHelper::kEpsilon &&
      (fit_to_page || params.print_to_pdf)) {
    content_width =
        static_cast<int>(static_cast<double>(content_width) * scale_factor);
    content_height =
        static_cast<int>(static_cast<double>(content_height) * scale_factor);
  }

  int margin_bottom =
      params.page_size.height() - content_height - params.margin_top;
  int margin_right =
      params.page_size.width() - content_width - params.margin_left;

  page_layout_in_points->content_width =
      ConvertUnit(content_width, dpi, kPointsPerInch);
  page_layout_in_points->content_height =
      ConvertUnit(content_height, dpi, kPointsPerInch);
  page_layout_in_points->margin_top =
      ConvertUnit(params.margin_top, dpi, kPointsPerInch);
  page_layout_in_points->margin_right =
      ConvertUnit(margin_right, dpi, kPointsPerInch);
  page_layout_in_points->margin_bottom =
      ConvertUnit(margin_bottom, dpi, kPointsPerInch);
  page_layout_in_points->margin_left =
      ConvertUnit(params.margin_left, dpi, kPointsPerInch);
}

void EnsureOrientationMatches(const PrintMsg_Print_Params& css_params,
                              PrintMsg_Print_Params* page_params) {
  if ((page_params->page_size.width() > page_params->page_size.height()) ==
      (css_params.page_size.width() > css_params.page_size.height())) {
    return;
  }

  // Swap the |width| and |height| values.
  page_params->page_size.SetSize(page_params->page_size.height(),
                                 page_params->page_size.width());
  page_params->content_size.SetSize(page_params->content_size.height(),
                                    page_params->content_size.width());
  page_params->printable_area.set_size(
      gfx::Size(page_params->printable_area.height(),
                page_params->printable_area.width()));
}

void ComputeWebKitPrintParamsInDesiredDpi(
    const PrintMsg_Print_Params& print_params,
    blink::WebPrintParams* webkit_print_params) {
  int dpi = GetDPI(&print_params);
  webkit_print_params->printerDPI = dpi;
  webkit_print_params->rasterizePDF = print_params.rasterize_pdf;
  webkit_print_params->printScalingOption = print_params.print_scaling_option;

  webkit_print_params->printContentArea.width = ConvertUnit(
      print_params.content_size.width(), dpi, print_params.desired_dpi);
  webkit_print_params->printContentArea.height = ConvertUnit(
      print_params.content_size.height(), dpi, print_params.desired_dpi);

  webkit_print_params->printableArea.x = ConvertUnit(
      print_params.printable_area.x(), dpi, print_params.desired_dpi);
  webkit_print_params->printableArea.y = ConvertUnit(
      print_params.printable_area.y(), dpi, print_params.desired_dpi);
  webkit_print_params->printableArea.width = ConvertUnit(
      print_params.printable_area.width(), dpi, print_params.desired_dpi);
  webkit_print_params->printableArea.height = ConvertUnit(
      print_params.printable_area.height(), dpi, print_params.desired_dpi);

  webkit_print_params->paperSize.width = ConvertUnit(
      print_params.page_size.width(), dpi, print_params.desired_dpi);
  webkit_print_params->paperSize.height = ConvertUnit(
      print_params.page_size.height(), dpi, print_params.desired_dpi);
}

blink::WebPlugin* GetPlugin(const blink::WebLocalFrame* frame) {
  return frame->document().isPluginDocument()
             ? frame->document().to<blink::WebPluginDocument>().plugin()
             : NULL;
}

bool PrintingNodeOrPdfFrame(const blink::WebLocalFrame* frame,
                            const blink::WebNode& node) {
  if (!node.isNull())
    return true;
  blink::WebPlugin* plugin = GetPlugin(frame);
  return plugin && plugin->supportsPaginatedPrint();
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
// Returns true if the current destination printer is PRINT_TO_PDF.
bool IsPrintToPdfRequested(const base::DictionaryValue& job_settings) {
  bool print_to_pdf = false;
  if (!job_settings.GetBoolean(kSettingPrintToPDF, &print_to_pdf))
    NOTREACHED();
  return print_to_pdf;
}

bool PrintingFrameHasPageSizeStyle(blink::WebLocalFrame* frame,
                                   int total_page_count) {
  if (!frame)
    return false;
  bool frame_has_custom_page_size_style = false;
  for (int i = 0; i < total_page_count; ++i) {
    if (frame->hasCustomPageSizeStyle(i)) {
      frame_has_custom_page_size_style = true;
      break;
    }
  }
  return frame_has_custom_page_size_style;
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

#if BUILDFLAG(ENABLE_PRINTING)
// Disable scaling when either:
// - The PDF specifies disabling scaling.
// - All the pages in the PDF are the same size,
// - |ignore_page_size| is false and the uniform size is the same as the paper
//   size.
bool PDFShouldDisableScalingBasedOnPreset(
    const blink::WebPrintPresetOptions& options,
    const PrintMsg_Print_Params& params,
    bool ignore_page_size) {
  if (options.isScalingDisabled)
    return true;

  if (!options.isPageSizeUniform)
    return false;

  int dpi = GetDPI(&params);
  if (!dpi) {
    // Likely |params| is invalid, in which case the return result does not
    // matter. Check for this so ConvertUnit() does not divide by zero.
    return true;
  }

  if (ignore_page_size)
    return false;

  blink::WebSize page_size(
      ConvertUnit(params.page_size.width(), dpi, kPointsPerInch),
      ConvertUnit(params.page_size.height(), dpi, kPointsPerInch));
  return options.uniformPageSize == page_size;
}

bool PDFShouldDisableScaling(blink::WebLocalFrame* frame,
                             const blink::WebNode& node,
                             const PrintMsg_Print_Params& params,
                             bool ignore_page_size) {
  const bool kDefaultPDFShouldDisableScalingSetting = true;
  blink::WebPrintPresetOptions preset_options;
  if (!frame->getPrintPresetOptionsForPlugin(node, &preset_options))
    return kDefaultPDFShouldDisableScalingSetting;
  return PDFShouldDisableScalingBasedOnPreset(preset_options, params,
                                              ignore_page_size);
}
#endif

#if BUILDFLAG(ENABLE_BASIC_PRINTING)
MarginType GetMarginsForPdf(blink::WebLocalFrame* frame,
                            const blink::WebNode& node,
                            const PrintMsg_Print_Params& params) {
  return PDFShouldDisableScaling(frame, node, params, false) ?
      NO_MARGINS : PRINTABLE_AREA_MARGINS;
}
#endif

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
bool FitToPageEnabled(const base::DictionaryValue& job_settings) {
  bool fit_to_paper_size = false;
  if (!job_settings.GetBoolean(kSettingFitToPageEnabled, &fit_to_paper_size)) {
    NOTREACHED();
  }
  return fit_to_paper_size;
}

// Returns the print scaling option to retain/scale/crop the source page size
// to fit the printable area of the paper.
//
// We retain the source page size when the current destination printer is
// SAVE_AS_PDF.
//
// We crop the source page size to fit the printable area or we print only the
// left top page contents when
// (1) Source is PDF and the user has requested not to fit to printable area
// via |job_settings|.
// (2) Source is PDF. This is the first preview request and print scaling
// option is disabled for initiator renderer plugin.
//
// In all other cases, we scale the source page to fit the printable area.
blink::WebPrintScalingOption GetPrintScalingOption(
    blink::WebLocalFrame* frame,
    const blink::WebNode& node,
    bool source_is_html,
    const base::DictionaryValue& job_settings,
    const PrintMsg_Print_Params& params) {
  if (params.print_to_pdf)
    return blink::WebPrintScalingOptionSourceSize;

  if (!source_is_html) {
    if (!FitToPageEnabled(job_settings))
      return blink::WebPrintScalingOptionNone;

    bool no_plugin_scaling = PDFShouldDisableScaling(frame, node, params,
                                                     true);
    if (params.is_first_request && no_plugin_scaling)
      return blink::WebPrintScalingOptionNone;
  }
  return blink::WebPrintScalingOptionFitToPrintableArea;
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

// Helper function to scale and round an integer value with a double valued
// scaling.
int ScaleAndRound(int value, double scaling) {
  return static_cast<int>(static_cast<double>(value) / scaling);
}

// Helper function to scale the width and height of a gfx::Size by scaling.
gfx::Size ScaleAndRoundSize(gfx::Size original, double scaling) {
  return gfx::Size(ScaleAndRound(original.width(), scaling),
                   ScaleAndRound(original.height(), scaling));
}

PrintMsg_Print_Params CalculatePrintParamsForCss(
    blink::WebLocalFrame* frame,
    int page_index,
    const PrintMsg_Print_Params& page_params,
    bool ignore_css_margins,
    bool fit_to_page,
    double* scale_factor) {
  PrintMsg_Print_Params css_params =
      GetCssPrintParams(frame, page_index, page_params);

  PrintMsg_Print_Params params = page_params;
  EnsureOrientationMatches(css_params, &params);

  params.content_size = ScaleAndRoundSize(params.content_size, *scale_factor);
  if (ignore_css_margins && fit_to_page)
    return params;

  PrintMsg_Print_Params result_params = css_params;
  // If not printing a pdf or fitting to page, scale the page size.
  double page_scaling = params.print_to_pdf ? 1.0f : *scale_factor;
  if (!fit_to_page) {
    result_params.page_size =
        ScaleAndRoundSize(result_params.page_size, page_scaling);
  }
  if (ignore_css_margins) {
    // Since not fitting to page, scale the page size and margins.
    params.margin_left = ScaleAndRound(params.margin_left, page_scaling);
    params.margin_top = ScaleAndRound(params.margin_top, page_scaling);
    params.page_size = ScaleAndRoundSize(params.page_size, page_scaling);

    result_params.margin_top = params.margin_top;
    result_params.margin_left = params.margin_left;

    DCHECK(!fit_to_page);
    // Since we are ignoring the margins, the css page size is no longer
    // valid for content.
    int default_margin_right = params.page_size.width() -
                               params.content_size.width() - params.margin_left;
    int default_margin_bottom = params.page_size.height() -
                                params.content_size.height() -
                                params.margin_top;
    result_params.content_size =
        gfx::Size(result_params.page_size.width() - result_params.margin_left -
                      default_margin_right,
                  result_params.page_size.height() - result_params.margin_top -
                      default_margin_bottom);
  } else {
    // Using the CSS parameters. Scale CSS content size.
    result_params.content_size =
        ScaleAndRoundSize(result_params.content_size, *scale_factor);
    if (fit_to_page) {
      double factor = FitPrintParamsToPage(params, &result_params);
      if (scale_factor)
        *scale_factor = (*scale_factor) * factor;
    } else {
      // Already scaled the page, need to also scale the CSS margins since they
      // are begin applied
      result_params.margin_left =
          ScaleAndRound(result_params.margin_left, page_scaling);
      result_params.margin_top =
          ScaleAndRound(result_params.margin_top, page_scaling);
    }
  }

  return result_params;
}

}  // namespace

FrameReference::FrameReference(blink::WebLocalFrame* frame) {
  Reset(frame);
}

FrameReference::FrameReference() {
  Reset(NULL);
}

FrameReference::~FrameReference() {
}

void FrameReference::Reset(blink::WebLocalFrame* frame) {
  if (frame) {
    view_ = frame->view();
    frame_ = frame;
  } else {
    view_ = NULL;
    frame_ = NULL;
  }
}

blink::WebLocalFrame* FrameReference::GetFrame() {
  if (view_ == NULL || frame_ == NULL)
    return NULL;
  for (blink::WebFrame* frame = view_->mainFrame(); frame != NULL;
       frame = frame->traverseNext()) {
    if (frame == frame_)
      return frame_;
  }
  return NULL;
}

blink::WebView* FrameReference::view() {
  return view_;
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
// static - Not anonymous so that platform implementations can use it.
void PrintWebViewHelper::PrintHeaderAndFooter(
    blink::WebCanvas* canvas,
    int page_number,
    int total_pages,
    const blink::WebFrame& source_frame,
    float webkit_scale_factor,
    const PageSizeMargins& page_layout,
    const PrintMsg_Print_Params& params) {
  SkAutoCanvasRestore auto_restore(canvas, true);
  canvas->scale(1 / webkit_scale_factor, 1 / webkit_scale_factor);

  blink::WebSize page_size(page_layout.margin_left + page_layout.margin_right +
                               page_layout.content_width,
                           page_layout.margin_top + page_layout.margin_bottom +
                               page_layout.content_height);

  blink::WebView* web_view =
      blink::WebView::create(nullptr, blink::WebPageVisibilityStateVisible);
  web_view->settings()->setJavaScriptEnabled(true);

  blink::WebFrameClient frame_client;
  blink::WebLocalFrame* frame = blink::WebLocalFrame::create(
      blink::WebTreeScopeType::Document, &frame_client);
  web_view->setMainFrame(frame);
  blink::WebFrameWidget::create(nullptr, web_view, frame);

  base::StringValue html(ResourceBundle::GetSharedInstance().GetLocalizedString(
      IDR_PRINT_PREVIEW_PAGE));
  // Load page with script to avoid async operations.
  ExecuteScript(frame, kPageLoadScriptFormat, html);

  std::unique_ptr<base::DictionaryValue> options(new base::DictionaryValue());
  options.reset(new base::DictionaryValue());
  options->SetDouble(kSettingHeaderFooterDate, base::Time::Now().ToJsTime());
  options->SetDouble("width", page_size.width);
  options->SetDouble("height", page_size.height);
  options->SetDouble("topMargin", page_layout.margin_top);
  options->SetDouble("bottomMargin", page_layout.margin_bottom);
  options->SetString("pageNumber",
                     base::StringPrintf("%d/%d", page_number, total_pages));

  options->SetString("url", params.url);
  base::string16 title = source_frame.document().title();
  options->SetString("title", title.empty() ? params.title : title);

  ExecuteScript(frame, kPageSetupScriptFormat, *options);

  blink::WebPrintParams webkit_params(page_size);
  webkit_params.printerDPI = GetDPI(&params);

  frame->printBegin(webkit_params);
  frame->printPage(0, canvas);
  frame->printEnd();

  web_view->close();
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

// static - Not anonymous so that platform implementations can use it.
float PrintWebViewHelper::RenderPageContent(blink::WebFrame* frame,
                                            int page_number,
                                            const gfx::Rect& canvas_area,
                                            const gfx::Rect& content_area,
                                            double scale_factor,
                                            blink::WebCanvas* canvas) {
  SkAutoCanvasRestore auto_restore(canvas, true);
  canvas->translate((content_area.x() - canvas_area.x()) / scale_factor,
                    (content_area.y() - canvas_area.y()) / scale_factor);
  return frame->printPage(page_number, canvas);
}

// Class that calls the Begin and End print functions on the frame and changes
// the size of the view temporarily to support full page printing..
class PrepareFrameAndViewForPrint : public blink::WebViewClient,
                                    public blink::WebFrameClient {
 public:
  PrepareFrameAndViewForPrint(const PrintMsg_Print_Params& params,
                              blink::WebLocalFrame* frame,
                              const blink::WebNode& node,
                              bool ignore_css_margins);
  ~PrepareFrameAndViewForPrint() override;

  // Optional. Replaces |frame_| with selection if needed. Will call |on_ready|
  // when completed.
  void CopySelectionIfNeeded(const WebPreferences& preferences,
                             const base::Closure& on_ready);

  // Prepares frame for printing.
  void StartPrinting();

  blink::WebLocalFrame* frame() { return frame_.GetFrame(); }

  const blink::WebNode& node() const { return node_to_print_; }

  int GetExpectedPageCount() const { return expected_pages_count_; }

  void FinishPrinting();

  bool IsLoadingSelection() {
    // It's not selection if not |owns_web_view_|.
    return owns_web_view_ && frame() && frame()->isLoading();
  }

 private:
  // blink::WebViewClient:
  void didStopLoading() override;
  // TODO(ojan): Remove this override and have this class use a non-null
  // layerTreeView.
  bool allowsBrokenNullLayerTreeView() const override;

  // blink::WebFrameClient:
  blink::WebLocalFrame* createChildFrame(
      blink::WebLocalFrame* parent,
      blink::WebTreeScopeType scope,
      const blink::WebString& name,
      const blink::WebString& unique_name,
      blink::WebSandboxFlags sandbox_flags,
      const blink::WebFrameOwnerProperties& frame_owner_properties) override;

  void CallOnReady();
  void ResizeForPrinting();
  void RestoreSize();
  void CopySelection(const WebPreferences& preferences);

  FrameReference frame_;
  blink::WebNode node_to_print_;
  bool owns_web_view_;
  blink::WebPrintParams web_print_params_;
  gfx::Size prev_view_size_;
  gfx::Size prev_scroll_offset_;
  int expected_pages_count_;
  base::Closure on_ready_;
  bool should_print_backgrounds_;
  bool should_print_selection_only_;
  bool is_printing_started_;

  base::WeakPtrFactory<PrepareFrameAndViewForPrint> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(PrepareFrameAndViewForPrint);
};

PrepareFrameAndViewForPrint::PrepareFrameAndViewForPrint(
    const PrintMsg_Print_Params& params,
    blink::WebLocalFrame* frame,
    const blink::WebNode& node,
    bool ignore_css_margins)
    : frame_(frame),
      node_to_print_(node),
      owns_web_view_(false),
      expected_pages_count_(0),
      should_print_backgrounds_(params.should_print_backgrounds),
      should_print_selection_only_(params.selection_only),
      is_printing_started_(false),
      weak_ptr_factory_(this) {
  PrintMsg_Print_Params print_params = params;
  if (!should_print_selection_only_ ||
      !PrintingNodeOrPdfFrame(frame, node_to_print_)) {
    bool fit_to_page =
        ignore_css_margins && IsWebPrintScalingOptionFitToPage(print_params);
    ComputeWebKitPrintParamsInDesiredDpi(params, &web_print_params_);
    frame->printBegin(web_print_params_, node_to_print_);
    double scale_factor = 1.0f;
#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    if (print_params.scale_factor >= PrintWebViewHelper::kEpsilon)
      scale_factor = print_params.scale_factor;
#endif
    print_params = CalculatePrintParamsForCss(
        frame, 0, print_params, ignore_css_margins, fit_to_page, &scale_factor);
    frame->printEnd();
  }
  ComputeWebKitPrintParamsInDesiredDpi(print_params, &web_print_params_);
}

PrepareFrameAndViewForPrint::~PrepareFrameAndViewForPrint() {
  FinishPrinting();
}

void PrepareFrameAndViewForPrint::ResizeForPrinting() {
  // Layout page according to printer page size. Since WebKit shrinks the
  // size of the page automatically (from 133.3% to 200%) we trick it to
  // think the page is 133.3% larger so the size of the page is correct for
  // minimum (default) scaling.
  // The scaling factor 1.25 was originally chosen as a magic number that
  // was 'about right'. However per https://crbug.com/273306 1.333 seems to be
  // the number that produces output with the correct physical size for elements
  // that are specified in cm, mm, pt etc.
  // This is important for sites that try to fill the page.
  gfx::Size print_layout_size(web_print_params_.printContentArea.width,
                              web_print_params_.printContentArea.height);
  print_layout_size.set_height(
      ScaleAndRound(print_layout_size.height(), kPrintingMinimumShrinkFactor));

  if (!frame())
    return;

  // Backup size and offset if it's a local frame.
  blink::WebView* web_view = frame_.view();
  if (blink::WebFrame* web_frame = web_view->mainFrame()) {
    if (web_frame->isWebLocalFrame())
      prev_scroll_offset_ = web_frame->getScrollOffset();
  }
  prev_view_size_ = web_view->size();

  web_view->resize(print_layout_size);
}

void PrepareFrameAndViewForPrint::StartPrinting() {
  blink::WebView* web_view = frame_.view();
  web_view->settings()->setShouldPrintBackgrounds(should_print_backgrounds_);
  expected_pages_count_ =
      frame()->printBegin(web_print_params_, node_to_print_);
  ResizeForPrinting();
  is_printing_started_ = true;
}

void PrepareFrameAndViewForPrint::CopySelectionIfNeeded(
    const WebPreferences& preferences,
    const base::Closure& on_ready) {
  on_ready_ = on_ready;
  if (should_print_selection_only_) {
    CopySelection(preferences);
  } else {
    // Call immediately, async call crashes scripting printing.
    CallOnReady();
  }
}

void PrepareFrameAndViewForPrint::CopySelection(
    const WebPreferences& preferences) {
  ResizeForPrinting();
  std::string url_str = "data:text/html;charset=utf-8,";
  url_str.append(
      net::EscapeQueryParamValue(frame()->selectionAsMarkup().utf8(), false));
  RestoreSize();
  // Create a new WebView with the same settings as the current display one.
  // Except that we disable javascript (don't want any active content running
  // on the page).
  WebPreferences prefs = preferences;
  prefs.javascript_enabled = false;

  blink::WebView* web_view =
      blink::WebView::create(this, blink::WebPageVisibilityStateVisible);
  owns_web_view_ = true;
  content::RenderView::ApplyWebPreferences(prefs, web_view);
  blink::WebLocalFrame* main_frame =
      blink::WebLocalFrame::create(blink::WebTreeScopeType::Document, this);
  web_view->setMainFrame(main_frame);
  blink::WebFrameWidget::create(this, web_view, main_frame);
  frame_.Reset(web_view->mainFrame()->toWebLocalFrame());
  node_to_print_.reset();

  // When loading is done this will call didStopLoading() and that will do the
  // actual printing.
  blink::WebURLRequest request = blink::WebURLRequest(GURL(url_str));
  frame()->loadRequest(request);
}

bool PrepareFrameAndViewForPrint::allowsBrokenNullLayerTreeView() const {
  return true;
}

void PrepareFrameAndViewForPrint::didStopLoading() {
  DCHECK(!on_ready_.is_null());
  // Don't call callback here, because it can delete |this| and WebView that is
  // called didStopLoading.
  base::ThreadTaskRunnerHandle::Get()->PostTask(
      FROM_HERE, base::Bind(&PrepareFrameAndViewForPrint::CallOnReady,
                            weak_ptr_factory_.GetWeakPtr()));
}

blink::WebLocalFrame* PrepareFrameAndViewForPrint::createChildFrame(
    blink::WebLocalFrame* parent,
    blink::WebTreeScopeType scope,
    const blink::WebString& name,
    const blink::WebString& unique_name,
    blink::WebSandboxFlags sandbox_flags,
    const blink::WebFrameOwnerProperties& frame_owner_properties) {
  blink::WebLocalFrame* frame = blink::WebLocalFrame::create(scope, this);
  parent->appendChild(frame);
  return frame;
}

void PrepareFrameAndViewForPrint::CallOnReady() {
  return on_ready_.Run();  // Can delete |this|.
}

void PrepareFrameAndViewForPrint::RestoreSize() {
  if (!frame())
    return;

  blink::WebView* web_view = frame_.GetFrame()->view();
  web_view->resize(prev_view_size_);
  if (blink::WebFrame* web_frame = web_view->mainFrame()) {
    if (web_frame->isWebLocalFrame())
      web_frame->setScrollOffset(prev_scroll_offset_);
  }
}

void PrepareFrameAndViewForPrint::FinishPrinting() {
  blink::WebLocalFrame* frame = frame_.GetFrame();
  if (frame) {
    blink::WebView* web_view = frame->view();
    if (is_printing_started_) {
      is_printing_started_ = false;
      if (!owns_web_view_) {
        web_view->settings()->setShouldPrintBackgrounds(false);
        RestoreSize();
      }
      frame->printEnd();
    }
    if (owns_web_view_) {
      DCHECK(!frame->isLoading());
      owns_web_view_ = false;
      frame->frameWidget()->close();
      web_view->close();
    }
  }
  frame_.Reset(NULL);
  on_ready_.Reset();
}

bool PrintWebViewHelper::Delegate::IsAskPrintSettingsEnabled() {
  return true;
}

bool PrintWebViewHelper::Delegate::IsScriptedPrintEnabled() {
  return true;
}

PrintWebViewHelper::PrintWebViewHelper(content::RenderFrame* render_frame,
                                       std::unique_ptr<Delegate> delegate)
    : content::RenderFrameObserver(render_frame),
      content::RenderFrameObserverTracker<PrintWebViewHelper>(render_frame),
      reset_prep_frame_view_(false),
      is_print_ready_metafile_sent_(false),
      ignore_css_margins_(false),
      is_printing_enabled_(true),
      notify_browser_of_print_failure_(true),
      print_for_preview_(false),
      delegate_(std::move(delegate)),
      print_node_in_progress_(false),
      is_loading_(false),
      is_scripted_preview_delayed_(false),
      ipc_nesting_level_(0),
      weak_ptr_factory_(this) {
  if (!delegate_->IsPrintPreviewEnabled())
    DisablePreview();
}

PrintWebViewHelper::~PrintWebViewHelper() {
}

// static
void PrintWebViewHelper::DisablePreview() {
  g_is_preview_enabled = false;
}

bool PrintWebViewHelper::IsScriptInitiatedPrintAllowed(
    blink::WebLocalFrame* frame,
    bool user_initiated) {
  if (!is_printing_enabled_ || !delegate_->IsScriptedPrintEnabled())
    return false;

  // If preview is enabled, then the print dialog is tab modal, and the user
  // can always close the tab on a mis-behaving page (the system print dialog
  // is app modal). If the print was initiated through user action, don't
  // throttle. Or, if the command line flag to skip throttling has been set.
  return user_initiated || g_is_preview_enabled ||
         scripting_throttler_.IsAllowed(frame);
}

void PrintWebViewHelper::DidStartProvisionalLoad() {
  is_loading_ = true;
}

void PrintWebViewHelper::DidFailProvisionalLoad(
    const blink::WebURLError& error) {
  DidFinishLoad();
}

void PrintWebViewHelper::DidFinishLoad() {
  is_loading_ = false;
  if (!on_stop_loading_closure_.is_null()) {
    on_stop_loading_closure_.Run();
    on_stop_loading_closure_.Reset();
  }
}

void PrintWebViewHelper::ScriptedPrint(bool user_initiated) {
  // Allow Prerendering to cancel this print request if necessary.
  if (delegate_->CancelPrerender(render_frame()))
    return;

  blink::WebLocalFrame* web_frame = render_frame()->GetWebFrame();
  if (!IsScriptInitiatedPrintAllowed(web_frame, user_initiated))
    return;

  if (delegate_->OverridePrint(web_frame))
    return;

  if (g_is_preview_enabled) {
#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    print_preview_context_.InitWithFrame(web_frame);
    RequestPrintPreview(PRINT_PREVIEW_SCRIPTED);
#endif
  } else {
#if BUILDFLAG(ENABLE_BASIC_PRINTING)
    Print(web_frame, blink::WebNode(), true /* is_scripted? */);
#endif
  }
  // WARNING: |this| may be gone at this point. Do not do any more work here and
  // just return.
}

bool PrintWebViewHelper::OnMessageReceived(const IPC::Message& message) {
  // The class is not designed to handle recursive messages. This is not
  // expected during regular flow. However, during rendering of content for
  // printing, lower level code may run nested message loop. E.g. PDF may has
  // script to show message box http://crbug.com/502562. In that moment browser
  // may receive updated printer capabilities and decide to restart print
  // preview generation. When this happened message handling function may
  // choose to ignore message or safely crash process.
  ++ipc_nesting_level_;

  auto self = weak_ptr_factory_.GetWeakPtr();

  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(PrintWebViewHelper, message)
#if BUILDFLAG(ENABLE_BASIC_PRINTING)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintPages, OnPrintPages)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintForSystemDialog, OnPrintForSystemDialog)
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
#if BUILDFLAG(ENABLE_BASIC_PRINTING) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintForPrintPreview, OnPrintForPrintPreview)
#endif
#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    IPC_MESSAGE_HANDLER(PrintMsg_InitiatePrintPreview, OnInitiatePrintPreview)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintPreview, OnPrintPreview)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintingDone, OnPrintingDone)
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
    IPC_MESSAGE_HANDLER(PrintMsg_SetPrintingEnabled, OnSetPrintingEnabled)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()

  // Check if |this| is still valid. e.g. when OnPrintPages() returns.
  if (self)
    --ipc_nesting_level_;
  return handled;
}

void PrintWebViewHelper::OnDestruct() {
  delete this;
}

#if BUILDFLAG(ENABLE_BASIC_PRINTING)
void PrintWebViewHelper::OnPrintPages() {
  if (ipc_nesting_level_> 1)
    return;

  blink::WebLocalFrame* frame = render_frame()->GetWebFrame();

  // If we are printing a PDF extension frame, find the plugin node and print
  // that instead.
  auto plugin = delegate_->GetPdfElement(frame);
  Print(frame, plugin, false /* is_scripted? */);
  // WARNING: |this| may be gone at this point. Do not do any more work here and
  // just return.
}

void PrintWebViewHelper::OnPrintForSystemDialog() {
  if (ipc_nesting_level_> 1)
    return;
  blink::WebLocalFrame* frame = print_preview_context_.source_frame();
  if (!frame) {
    NOTREACHED();
    return;
  }
  Print(frame, print_preview_context_.source_node(), false);
  // WARNING: |this| may be gone at this point. Do not do any more work here and
  // just return.
}
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)

#if BUILDFLAG(ENABLE_BASIC_PRINTING) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
void PrintWebViewHelper::OnPrintForPrintPreview(
    const base::DictionaryValue& job_settings) {
  CHECK_LE(ipc_nesting_level_, 1);
  // If still not finished with earlier print request simply ignore.
  if (prep_frame_view_)
    return;

  blink::WebDocument document = render_frame()->GetWebFrame()->document();
  // <object>/<iframe> with id="pdf-viewer" is created in
  // chrome/browser/resources/print_preview/print_preview.js
  blink::WebElement pdf_element = document.getElementById("pdf-viewer");
  if (pdf_element.isNull()) {
    NOTREACHED();
    return;
  }

  // The out-of-process plugin element is nested within a frame. In tests, there
  // may not be an iframe containing the out-of-process plugin, so continue with
  // the element with ID "pdf-viewer" if it isn't an iframe.
  blink::WebLocalFrame* plugin_frame = pdf_element.document().frame();
  blink::WebElement plugin_element = pdf_element;
  if (pdf_element.hasHTMLTagName("iframe")) {
    plugin_frame = blink::WebLocalFrame::fromFrameOwnerElement(pdf_element);
    plugin_element = delegate_->GetPdfElement(plugin_frame);
    if (plugin_element.isNull()) {
      NOTREACHED();
      return;
    }
  }

  // Set |print_for_preview_| flag and autoreset it to back to original
  // on return.
  base::AutoReset<bool> set_printing_flag(&print_for_preview_, true);

  if (!UpdatePrintSettings(plugin_frame, plugin_element, job_settings)) {
    LOG(ERROR) << "UpdatePrintSettings failed";
    DidFinishPrinting(FAIL_PRINT);
    return;
  }

  // Print page onto entire page not just printable area. Preview PDF already
  // has content in correct position taking into account page size and printable
  // area.
  // TODO(vitalybuka) : Make this consistent on all platform. This change
  // affects Windows only. On Linux and OSX RenderPagesForPrint does not use
  // printable_area. Also we can't change printable_area deeper inside
  // RenderPagesForPrint for Windows, because it's used also by native
  // printing and it expects real printable_area value.
  // See http://crbug.com/123408
  PrintMsg_Print_Params& print_params = print_pages_params_->params;
  print_params.printable_area = gfx::Rect(print_params.page_size);

  // Render Pages for printing.
  if (!RenderPagesForPrint(plugin_frame, plugin_element)) {
    LOG(ERROR) << "RenderPagesForPrint failed";
    DidFinishPrinting(FAIL_PRINT);
  }
}
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING) && BUILDFLAG(ENABLE_PRINT_PREVIEW)

void PrintWebViewHelper::GetPageSizeAndContentAreaFromPageLayout(
    const PageSizeMargins& page_layout_in_points,
    gfx::Size* page_size,
    gfx::Rect* content_area) {
  *page_size = gfx::Size(
      page_layout_in_points.content_width + page_layout_in_points.margin_right +
          page_layout_in_points.margin_left,
      page_layout_in_points.content_height + page_layout_in_points.margin_top +
          page_layout_in_points.margin_bottom);
  *content_area = gfx::Rect(page_layout_in_points.margin_left,
                            page_layout_in_points.margin_top,
                            page_layout_in_points.content_width,
                            page_layout_in_points.content_height);
}

void PrintWebViewHelper::UpdateFrameMarginsCssInfo(
    const base::DictionaryValue& settings) {
  int margins_type = 0;
  if (!settings.GetInteger(kSettingMarginsType, &margins_type))
    margins_type = DEFAULT_MARGINS;
  ignore_css_margins_ = (margins_type != DEFAULT_MARGINS);
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
void PrintWebViewHelper::OnPrintPreview(const base::DictionaryValue& settings) {
  if (ipc_nesting_level_ > 1)
    return;

  print_preview_context_.OnPrintPreview();

  UMA_HISTOGRAM_ENUMERATION("PrintPreview.PreviewEvent",
                            PREVIEW_EVENT_REQUESTED, PREVIEW_EVENT_MAX);

  if (!print_preview_context_.source_frame()) {
    DidFinishPrinting(FAIL_PREVIEW);
    return;
  }

  if (!UpdatePrintSettings(print_preview_context_.source_frame(),
                           print_preview_context_.source_node(), settings)) {
    if (print_preview_context_.last_error() != PREVIEW_ERROR_BAD_SETTING) {
      Send(new PrintHostMsg_PrintPreviewInvalidPrinterSettings(
          routing_id(), print_pages_params_
                            ? print_pages_params_->params.document_cookie
                            : 0));
      notify_browser_of_print_failure_ = false;  // Already sent.
    }
    DidFinishPrinting(FAIL_PREVIEW);
    return;
  }

  // Set the options from document if we are previewing a pdf and send a
  // message to browser.
  if (print_pages_params_->params.is_first_request &&
      !print_preview_context_.IsModifiable()) {
    PrintHostMsg_SetOptionsFromDocument_Params options;
    if (SetOptionsFromPdfDocument(&options))
      Send(new PrintHostMsg_SetOptionsFromDocument(routing_id(), options));
  }

  is_print_ready_metafile_sent_ = false;

  // PDF printer device supports alpha blending.
  print_pages_params_->params.supports_alpha_blend = true;

  bool generate_draft_pages = false;
  if (!settings.GetBoolean(kSettingGenerateDraftData, &generate_draft_pages)) {
    NOTREACHED();
  }
  print_preview_context_.set_generate_draft_pages(generate_draft_pages);

  PrepareFrameForPreviewDocument();
}

void PrintWebViewHelper::PrepareFrameForPreviewDocument() {
  reset_prep_frame_view_ = false;

  if (!print_pages_params_ || CheckForCancel()) {
    DidFinishPrinting(FAIL_PREVIEW);
    return;
  }

  // Don't reset loading frame or WebKit will fail assert. Just retry when
  // current selection is loaded.
  if (prep_frame_view_ && prep_frame_view_->IsLoadingSelection()) {
    reset_prep_frame_view_ = true;
    return;
  }

  const PrintMsg_Print_Params& print_params = print_pages_params_->params;
  prep_frame_view_.reset(new PrepareFrameAndViewForPrint(
      print_params, print_preview_context_.source_frame(),
      print_preview_context_.source_node(), ignore_css_margins_));
  prep_frame_view_->CopySelectionIfNeeded(
      render_frame()->GetWebkitPreferences(),
      base::Bind(&PrintWebViewHelper::OnFramePreparedForPreviewDocument,
                 base::Unretained(this)));
}

void PrintWebViewHelper::OnFramePreparedForPreviewDocument() {
  if (reset_prep_frame_view_) {
    PrepareFrameForPreviewDocument();
    return;
  }
  DidFinishPrinting(CreatePreviewDocument() ? OK : FAIL_PREVIEW);
}

bool PrintWebViewHelper::CreatePreviewDocument() {
  if (!print_pages_params_ || CheckForCancel())
    return false;

  UMA_HISTOGRAM_ENUMERATION("PrintPreview.PreviewEvent",
                            PREVIEW_EVENT_CREATE_DOCUMENT, PREVIEW_EVENT_MAX);

  const PrintMsg_Print_Params& print_params = print_pages_params_->params;
  const std::vector<int>& pages = print_pages_params_->pages;

  if (!print_preview_context_.CreatePreviewDocument(prep_frame_view_.release(),
                                                    pages)) {
    return false;
  }

  PageSizeMargins default_page_layout;
  double scale_factor =
      print_params.scale_factor >= kEpsilon ? print_params.scale_factor : 1.0f;

  ComputePageLayoutInPointsForCss(print_preview_context_.prepared_frame(), 0,
                                  print_params, ignore_css_margins_,
                                  &scale_factor, &default_page_layout);
  bool has_page_size_style =
      PrintingFrameHasPageSizeStyle(print_preview_context_.prepared_frame(),
                                    print_preview_context_.total_page_count());
  int dpi = GetDPI(&print_params);

  gfx::Rect printable_area_in_points(
      ConvertUnit(print_params.printable_area.x(), dpi, kPointsPerInch),
      ConvertUnit(print_params.printable_area.y(), dpi, kPointsPerInch),
      ConvertUnit(print_params.printable_area.width(), dpi, kPointsPerInch),
      ConvertUnit(print_params.printable_area.height(), dpi, kPointsPerInch));

  double fit_to_page_scale_factor = 1.0f;
  if (!print_preview_context_.IsModifiable()) {
    blink::WebLocalFrame* source_frame = print_preview_context_.source_frame();
    const blink::WebNode& source_node = print_preview_context_.source_node();
    blink::WebPrintPresetOptions preset_options;
    if (source_frame->getPrintPresetOptionsForPlugin(source_node,
                                                     &preset_options)) {
      if (preset_options.isPageSizeUniform) {
        double scale_width =
            static_cast<double>(printable_area_in_points.width()) /
            static_cast<double>(preset_options.uniformPageSize.width);
        double scale_height =
            static_cast<double>(printable_area_in_points.height()) /
            static_cast<double>(preset_options.uniformPageSize.height);
        fit_to_page_scale_factor = std::min(scale_width, scale_height);
      } else {
        fit_to_page_scale_factor = 0.0f;
      }
    }
  }
  int fit_to_page_scaling = static_cast<int>(100.0f * fit_to_page_scale_factor);
  // Margins: Send default page layout to browser process.
  Send(new PrintHostMsg_DidGetDefaultPageLayout(routing_id(),
                                                default_page_layout,
                                                printable_area_in_points,
                                                has_page_size_style));

  PrintHostMsg_DidGetPreviewPageCount_Params params;
  params.page_count = print_preview_context_.total_page_count();
  params.is_modifiable = print_preview_context_.IsModifiable();
  params.fit_to_page_scaling = fit_to_page_scaling;
  params.document_cookie = print_params.document_cookie;
  params.preview_request_id = print_params.preview_request_id;
  params.clear_preview_data = print_preview_context_.generate_draft_pages();
  Send(new PrintHostMsg_DidGetPreviewPageCount(routing_id(), params));
  if (CheckForCancel())
    return false;

  while (!print_preview_context_.IsFinalPageRendered()) {
    int page_number = print_preview_context_.GetNextPageNumber();
    DCHECK_GE(page_number, 0);
    if (!RenderPreviewPage(page_number, print_params))
      return false;

    if (CheckForCancel())
      return false;

    // We must call PrepareFrameAndViewForPrint::FinishPrinting() (by way of
    // print_preview_context_.AllPagesRendered()) before calling
    // FinalizePrintReadyDocument() when printing a PDF because the plugin
    // code does not generate output until we call FinishPrinting().  We do not
    // generate draft pages for PDFs, so IsFinalPageRendered() and
    // IsLastPageOfPrintReadyMetafile() will be true in the same iteration of
    // the loop.
    if (print_preview_context_.IsFinalPageRendered())
      print_preview_context_.AllPagesRendered();

    if (print_preview_context_.IsLastPageOfPrintReadyMetafile()) {
      DCHECK(print_preview_context_.IsModifiable() ||
             print_preview_context_.IsFinalPageRendered());
      if (!FinalizePrintReadyDocument())
        return false;
    }
  }
  print_preview_context_.Finished();
  return true;
}

#if !defined(OS_MACOSX) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
bool PrintWebViewHelper::RenderPreviewPage(
    int page_number,
    const PrintMsg_Print_Params& print_params) {
  PrintMsg_PrintPage_Params page_params;
  page_params.params = print_params;
  page_params.page_number = page_number;
  std::unique_ptr<PdfMetafileSkia> draft_metafile;
  PdfMetafileSkia* initial_render_metafile = print_preview_context_.metafile();
  if (print_preview_context_.IsModifiable() && is_print_ready_metafile_sent_) {
    draft_metafile.reset(new PdfMetafileSkia(PDF_SKIA_DOCUMENT_TYPE));
    initial_render_metafile = draft_metafile.get();
  }

  base::TimeTicks begin_time = base::TimeTicks::Now();
  PrintPageInternal(page_params, print_preview_context_.prepared_frame(),
                    initial_render_metafile, nullptr, nullptr);
  print_preview_context_.RenderedPreviewPage(
      base::TimeTicks::Now() - begin_time);
  if (draft_metafile.get()) {
    draft_metafile->FinishDocument();
  } else if (print_preview_context_.IsModifiable() &&
             print_preview_context_.generate_draft_pages()) {
    DCHECK(!draft_metafile.get());
    draft_metafile =
        print_preview_context_.metafile()->GetMetafileForCurrentPage(
            PDF_SKIA_DOCUMENT_TYPE);
  }
  return PreviewPageRendered(page_number, draft_metafile.get());
}
#endif  // !defined(OS_MACOSX) && BUILDFLAG(ENABLE_PRINT_PREVIEW)

bool PrintWebViewHelper::FinalizePrintReadyDocument() {
  DCHECK(!is_print_ready_metafile_sent_);
  print_preview_context_.FinalizePrintReadyDocument();

  PdfMetafileSkia* metafile = print_preview_context_.metafile();
  PrintHostMsg_DidPreviewDocument_Params preview_params;

  // Ask the browser to create the shared memory for us.
  if (!CopyMetafileDataToSharedMem(*metafile,
                                   &(preview_params.metafile_data_handle))) {
    LOG(ERROR) << "CopyMetafileDataToSharedMem failed";
    print_preview_context_.set_error(PREVIEW_ERROR_METAFILE_COPY_FAILED);
    return false;
  }

  preview_params.data_size = metafile->GetDataSize();
  preview_params.document_cookie = print_pages_params_->params.document_cookie;
  preview_params.expected_pages_count =
      print_preview_context_.total_page_count();
  preview_params.modifiable = print_preview_context_.IsModifiable();
  preview_params.preview_request_id =
      print_pages_params_->params.preview_request_id;

  is_print_ready_metafile_sent_ = true;

  Send(new PrintHostMsg_MetafileReadyForPrinting(routing_id(), preview_params));
  return true;
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

void PrintWebViewHelper::OnPrintingDone(bool success) {
  if (ipc_nesting_level_ > 1)
    return;
  notify_browser_of_print_failure_ = false;
  if (!success)
    LOG(ERROR) << "Failure in OnPrintingDone";
  DidFinishPrinting(success ? OK : FAIL_PRINT);
}

void PrintWebViewHelper::OnSetPrintingEnabled(bool enabled) {
  is_printing_enabled_ = enabled;
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
void PrintWebViewHelper::OnInitiatePrintPreview(bool has_selection) {
  if (ipc_nesting_level_ > 1)
    return;

  blink::WebLocalFrame* frame = render_frame()->GetWebFrame();

  // If we are printing a PDF extension frame, find the plugin node and print
  // that instead.
  auto plugin = delegate_->GetPdfElement(frame);
  if (!plugin.isNull()) {
    PrintNode(plugin);
    return;
  }
  print_preview_context_.InitWithFrame(frame);
  RequestPrintPreview(has_selection
                          ? PRINT_PREVIEW_USER_INITIATED_SELECTION
                          : PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME);
}
#endif

bool PrintWebViewHelper::IsPrintingEnabled() const {
  return is_printing_enabled_;
}

void PrintWebViewHelper::PrintNode(const blink::WebNode& node) {
  if (node.isNull() || !node.document().frame()) {
    // This can occur when the context menu refers to an invalid WebNode.
    // See http://crbug.com/100890#c17 for a repro case.
    return;
  }

  if (print_node_in_progress_) {
    // This can happen as a result of processing sync messages when printing
    // from ppapi plugins. It's a rare case, so its OK to just fail here.
    // See http://crbug.com/159165.
    return;
  }

  print_node_in_progress_ = true;

  if (g_is_preview_enabled) {
#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    print_preview_context_.InitWithNode(node);
    RequestPrintPreview(PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE);
#endif
  } else {
#if BUILDFLAG(ENABLE_BASIC_PRINTING)
    // Make a copy of the node, in case RenderView::OnContextMenuClosed() resets
    // its |context_menu_node_|.
    blink::WebNode duplicate_node(node);

    auto self = weak_ptr_factory_.GetWeakPtr();
    Print(duplicate_node.document().frame(), duplicate_node,
          false /* is_scripted? */);
    // Check if |this| is still valid.
    if (!self)
      return;
#endif
  }

  print_node_in_progress_ = false;
}

#if BUILDFLAG(ENABLE_BASIC_PRINTING)
void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
                               const blink::WebNode& node,
                               bool is_scripted) {
  // If still not finished with earlier print request simply ignore.
  if (prep_frame_view_)
    return;

  FrameReference frame_ref(frame);

  int expected_page_count = 0;
  if (!CalculateNumberOfPages(frame, node, &expected_page_count)) {
    DidFinishPrinting(FAIL_PRINT_INIT);
    return;  // Failed to init print page settings.
  }

  // Some full screen plugins can say they don't want to print.
  if (!expected_page_count) {
    DidFinishPrinting(FAIL_PRINT);
    return;
  }

  // Ask the browser to show UI to retrieve the final print settings.
  if (delegate_->IsAskPrintSettingsEnabled()) {
    // PrintHostMsg_ScriptedPrint in GetPrintSettingsFromUser() will reset
    // |print_scaling_option|, so save the value here and restore it afterwards.
    blink::WebPrintScalingOption scaling_option =
        print_pages_params_->params.print_scaling_option;

    PrintMsg_PrintPages_Params print_settings;
    auto self = weak_ptr_factory_.GetWeakPtr();
    GetPrintSettingsFromUser(frame_ref.GetFrame(), node, expected_page_count,
                             is_scripted, &print_settings);
    // Check if |this| is still valid.
    if (!self)
      return;

    print_settings.params.print_scaling_option = scaling_option;
    SetPrintPagesParams(print_settings);
    if (!print_settings.params.dpi || !print_settings.params.document_cookie) {
      DidFinishPrinting(OK);  // Release resources and fail silently on failure.
      return;
    }
  }

  // Render Pages for printing.
  if (!RenderPagesForPrint(frame_ref.GetFrame(), node)) {
    LOG(ERROR) << "RenderPagesForPrint failed";
    DidFinishPrinting(FAIL_PRINT);
  }
  scripting_throttler_.Reset();
}
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)

void PrintWebViewHelper::DidFinishPrinting(PrintingResult result) {
  switch (result) {
    case OK:
      break;

    case FAIL_PRINT_INIT:
      DCHECK(!notify_browser_of_print_failure_);
      break;

    case FAIL_PRINT:
      if (notify_browser_of_print_failure_ && print_pages_params_) {
        int cookie = print_pages_params_->params.document_cookie;
        Send(new PrintHostMsg_PrintingFailed(routing_id(), cookie));
      }
      break;

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    case FAIL_PREVIEW:
      int cookie =
          print_pages_params_ ? print_pages_params_->params.document_cookie : 0;
      if (notify_browser_of_print_failure_) {
        LOG(ERROR) << "CreatePreviewDocument failed";
        Send(new PrintHostMsg_PrintPreviewFailed(routing_id(), cookie));
      } else {
        Send(new PrintHostMsg_PrintPreviewCancelled(routing_id(), cookie));
      }
      print_preview_context_.Failed(notify_browser_of_print_failure_);
      break;
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
  }
  prep_frame_view_.reset();
  print_pages_params_.reset();
  notify_browser_of_print_failure_ = true;
}

#if BUILDFLAG(ENABLE_BASIC_PRINTING)
void PrintWebViewHelper::OnFramePreparedForPrintPages() {
  PrintPages();
  FinishFramePrinting();
}

void PrintWebViewHelper::PrintPages() {
  if (!prep_frame_view_)  // Printing is already canceled or failed.
    return;

  prep_frame_view_->StartPrinting();

  int page_count = prep_frame_view_->GetExpectedPageCount();
  if (!page_count) {
    LOG(ERROR) << "Can't print 0 pages.";
    return DidFinishPrinting(FAIL_PRINT);
  }

  const PrintMsg_PrintPages_Params& params = *print_pages_params_;
  const PrintMsg_Print_Params& print_params = params.params;

#if !defined(OS_ANDROID)
  // TODO(vitalybuka): should be page_count or valid pages from params.pages.
  // See http://crbug.com/161576
  Send(new PrintHostMsg_DidGetPrintedPagesCount(routing_id(),
                                                print_params.document_cookie,
                                                page_count));
#endif  // !defined(OS_ANDROID)

  if (print_params.preview_ui_id < 0) {
    // Printing for system dialog.
    int printed_count = params.pages.empty() ? page_count : params.pages.size();
    UMA_HISTOGRAM_COUNTS("PrintPreview.PageCount.SystemDialog", printed_count);
  }

  if (!PrintPagesNative(prep_frame_view_->frame(), page_count)) {
    LOG(ERROR) << "Printing failed.";
    return DidFinishPrinting(FAIL_PRINT);
  }
}

void PrintWebViewHelper::FinishFramePrinting() {
  prep_frame_view_.reset();
}
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)

// static - Not anonymous so that platform implementations can use it.
void PrintWebViewHelper::ComputePageLayoutInPointsForCss(
    blink::WebLocalFrame* frame,
    int page_index,
    const PrintMsg_Print_Params& page_params,
    bool ignore_css_margins,
    double* scale_factor,
    PageSizeMargins* page_layout_in_points) {
  double input_scale_factor = *scale_factor;
  PrintMsg_Print_Params params = CalculatePrintParamsForCss(
      frame, page_index, page_params, ignore_css_margins,
      IsWebPrintScalingOptionFitToPage(page_params), scale_factor);
  CalculatePageLayoutFromPrintParams(params, input_scale_factor,
                                     page_layout_in_points);
}

// static - Not anonymous so that platform implementations can use it.
std::vector<int> PrintWebViewHelper::GetPrintedPages(
    const PrintMsg_PrintPages_Params& params,
    int page_count) {
  std::vector<int> printed_pages;
  if (params.pages.empty()) {
    for (int i = 0; i < page_count; ++i) {
      printed_pages.push_back(i);
    }
  } else {
    for (int page : params.pages) {
      if (page >= 0 && page < page_count) {
        printed_pages.push_back(page);
      }
    }
  }
  return printed_pages;
}

bool PrintWebViewHelper::InitPrintSettings(bool fit_to_paper_size) {
  PrintMsg_PrintPages_Params settings;
  Send(new PrintHostMsg_GetDefaultPrintSettings(routing_id(),
                                                &settings.params));
  // Check if the printer returned any settings, if the settings is empty, we
  // can safely assume there are no printer drivers configured. So we safely
  // terminate.
  bool result = true;
  if (!PrintMsg_Print_Params_IsValid(settings.params))
    result = false;

  // Reset to default values.
  ignore_css_margins_ = false;
  settings.pages.clear();

  settings.params.print_scaling_option = blink::WebPrintScalingOptionSourceSize;
  if (fit_to_paper_size) {
    settings.params.print_scaling_option =
        blink::WebPrintScalingOptionFitToPrintableArea;
  }

  SetPrintPagesParams(settings);
  return result;
}

bool PrintWebViewHelper::CalculateNumberOfPages(blink::WebLocalFrame* frame,
                                                const blink::WebNode& node,
                                                int* number_of_pages) {
  DCHECK(frame);
  bool fit_to_paper_size = !(PrintingNodeOrPdfFrame(frame, node));
  if (!InitPrintSettings(fit_to_paper_size)) {
    notify_browser_of_print_failure_ = false;
    Send(new PrintHostMsg_ShowInvalidPrinterSettingsError(routing_id()));
    return false;
  }

  const PrintMsg_Print_Params& params = print_pages_params_->params;
  PrepareFrameAndViewForPrint prepare(params, frame, node, ignore_css_margins_);
  prepare.StartPrinting();

  *number_of_pages = prepare.GetExpectedPageCount();
  return true;
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
bool PrintWebViewHelper::SetOptionsFromPdfDocument(
    PrintHostMsg_SetOptionsFromDocument_Params* options) {
  blink::WebLocalFrame* source_frame = print_preview_context_.source_frame();
  const blink::WebNode& source_node = print_preview_context_.source_node();

  blink::WebPrintPresetOptions preset_options;
  if (!source_frame->getPrintPresetOptionsForPlugin(source_node,
                                                    &preset_options)) {
    return false;
  }

  options->is_scaling_disabled = PDFShouldDisableScalingBasedOnPreset(
      preset_options, print_pages_params_->params, false);
  options->copies = preset_options.copies;

  // TODO(thestig) This should be a straight pass-through, but print preview
  // does not currently support short-edge printing.
  switch (preset_options.duplexMode) {
    case blink::WebSimplex:
      options->duplex = SIMPLEX;
      break;
    case blink::WebLongEdge:
      options->duplex = LONG_EDGE;
      break;
    default:
      options->duplex = UNKNOWN_DUPLEX_MODE;
      break;
  }
  return true;
}

bool PrintWebViewHelper::UpdatePrintSettings(
    blink::WebLocalFrame* frame,
    const blink::WebNode& node,
    const base::DictionaryValue& passed_job_settings) {
  const base::DictionaryValue* job_settings = &passed_job_settings;
  base::DictionaryValue modified_job_settings;
  if (job_settings->empty()) {
    if (!print_for_preview_)
      print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
    return false;
  }

  bool source_is_html = true;
  if (print_for_preview_) {
    if (!job_settings->GetBoolean(kSettingPreviewModifiable, &source_is_html)) {
      NOTREACHED();
    }
  } else {
    source_is_html = !PrintingNodeOrPdfFrame(frame, node);
  }

  if (print_for_preview_ || !source_is_html) {
    modified_job_settings.MergeDictionary(job_settings);
    modified_job_settings.SetBoolean(kSettingHeaderFooterEnabled, false);
    modified_job_settings.SetInteger(kSettingMarginsType, NO_MARGINS);
    job_settings = &modified_job_settings;
  }

  // Send the cookie so that UpdatePrintSettings can reuse PrinterQuery when
  // possible.
  int cookie =
      print_pages_params_ ? print_pages_params_->params.document_cookie : 0;
  PrintMsg_PrintPages_Params settings;
  bool canceled = false;
  Send(new PrintHostMsg_UpdatePrintSettings(routing_id(), cookie, *job_settings,
                                            &settings, &canceled));
  if (canceled) {
    notify_browser_of_print_failure_ = false;
    return false;
  }

  if (!job_settings->GetInteger(kPreviewUIID, &settings.params.preview_ui_id)) {
    NOTREACHED();
    print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
    return false;
  }

  if (!print_for_preview_) {
    // Validate expected print preview settings.
    if (!job_settings->GetInteger(kPreviewRequestID,
                                  &settings.params.preview_request_id) ||
        !job_settings->GetBoolean(kIsFirstRequest,
                                  &settings.params.is_first_request)) {
      NOTREACHED();
      print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
      return false;
    }

    settings.params.print_to_pdf = IsPrintToPdfRequested(*job_settings);
    UpdateFrameMarginsCssInfo(*job_settings);
    settings.params.print_scaling_option = GetPrintScalingOption(
        frame, node, source_is_html, *job_settings, settings.params);
  }

  SetPrintPagesParams(settings);

  if (PrintMsg_Print_Params_IsValid(settings.params))
    return true;

  if (print_for_preview_)
    Send(new PrintHostMsg_ShowInvalidPrinterSettingsError(routing_id()));
  else
    print_preview_context_.set_error(PREVIEW_ERROR_INVALID_PRINTER_SETTINGS);
  return false;
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

#if BUILDFLAG(ENABLE_BASIC_PRINTING)
void PrintWebViewHelper::GetPrintSettingsFromUser(
    blink::WebLocalFrame* frame,
    const blink::WebNode& node,
    int expected_pages_count,
    bool is_scripted,
    PrintMsg_PrintPages_Params* print_settings) {
  PrintHostMsg_ScriptedPrint_Params params;
  params.cookie = print_pages_params_->params.document_cookie;
  params.has_selection = frame->hasSelection();
  params.expected_pages_count = expected_pages_count;
  MarginType margin_type = DEFAULT_MARGINS;
  if (PrintingNodeOrPdfFrame(frame, node))
    margin_type = GetMarginsForPdf(frame, node, print_pages_params_->params);
  params.margin_type = margin_type;
  params.is_scripted = is_scripted;
  params.is_modifiable = !PrintingNodeOrPdfFrame(frame, node);

  Send(new PrintHostMsg_DidShowPrintDialog(routing_id()));

  print_pages_params_.reset();

  auto msg = base::MakeUnique<PrintHostMsg_ScriptedPrint>(
      routing_id(), params, print_settings);
  msg->EnableMessagePumping();
  Send(msg.release());
  // WARNING: |this| may be gone at this point. Do not do any more work here
  // and just return.
}

bool PrintWebViewHelper::RenderPagesForPrint(blink::WebLocalFrame* frame,
                                             const blink::WebNode& node) {
  if (!frame || prep_frame_view_)
    return false;

  const PrintMsg_PrintPages_Params& params = *print_pages_params_;
  const PrintMsg_Print_Params& print_params = params.params;
  prep_frame_view_.reset(new PrepareFrameAndViewForPrint(
      print_params, frame, node, ignore_css_margins_));
  DCHECK(!print_pages_params_->params.selection_only ||
         print_pages_params_->pages.empty());
  prep_frame_view_->CopySelectionIfNeeded(
      render_frame()->GetWebkitPreferences(),
      base::Bind(&PrintWebViewHelper::OnFramePreparedForPrintPages,
                 base::Unretained(this)));
  return true;
}
#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)

#if !defined(OS_MACOSX)
void PrintWebViewHelper::PrintPageInternal(
    const PrintMsg_PrintPage_Params& params,
    blink::WebLocalFrame* frame,
    PdfMetafileSkia* metafile,
    gfx::Size* page_size_in_dpi,
    gfx::Rect* content_area_in_dpi) {
  PageSizeMargins page_layout_in_points;

  double css_scale_factor = 1.0f;
#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    if (params.params.scale_factor >= kEpsilon)
      css_scale_factor = params.params.scale_factor;
#endif
  ComputePageLayoutInPointsForCss(frame, params.page_number, params.params,
                                  ignore_css_margins_, &css_scale_factor,
                                  &page_layout_in_points);
  gfx::Size page_size;
  gfx::Rect content_area;
  GetPageSizeAndContentAreaFromPageLayout(page_layout_in_points, &page_size,
                                          &content_area);
  int dpi = static_cast<int>(params.params.dpi);
  // Calculate the actual page size and content area in dpi.
  if (page_size_in_dpi) {
    // Windows uses this for the actual page size. We have scaled page size
    // to get blink to reflow the page, so scale it back to the real size
    // before returning it.
    *page_size_in_dpi =
        gfx::Size(static_cast<int>(ConvertUnitDouble(page_size.width(),
                                                     kPointsPerInch, dpi) *
                                   css_scale_factor),
                  static_cast<int>(ConvertUnitDouble(page_size.height(),
                                                     kPointsPerInch, dpi) *
                                   css_scale_factor));
  }

  if (content_area_in_dpi) {
    // Output PDF matches paper size and should be printer edge to edge.
    *content_area_in_dpi =
        gfx::Rect(0, 0, page_size_in_dpi->width(), page_size_in_dpi->height());
  }

  gfx::Rect canvas_area =
      params.params.display_header_footer ? gfx::Rect(page_size) : content_area;

  // TODO(thestig): Figure out why Linux is different.
#if defined(OS_WIN)
  float webkit_page_shrink_factor =
      frame->getPrintPageShrink(params.page_number);
  float scale_factor = css_scale_factor * webkit_page_shrink_factor;
#else
  float scale_factor = css_scale_factor;
#endif

  SkCanvas* canvas = metafile->GetVectorCanvasForNewPage(
      page_size, canvas_area, scale_factor);
  if (!canvas)
    return;

  MetafileSkiaWrapper::SetMetafileOnCanvas(*canvas, metafile);

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
  if (params.params.display_header_footer) {
    // TODO(thestig): Figure out why Linux needs this. It is almost certainly
    // |printingMinimumShrinkFactor| from Blink.
#if defined(OS_WIN)
    const float fudge_factor = 1;
#else
    const float fudge_factor = kPrintingMinimumShrinkFactor;
#endif
    // |page_number| is 0-based, so 1 is added.
    PrintHeaderAndFooter(canvas, params.page_number + 1,
                         print_preview_context_.total_page_count(), *frame,
                         scale_factor / fudge_factor, page_layout_in_points,
                         params.params);
  }
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

  float webkit_scale_factor =
      RenderPageContent(frame, params.page_number, canvas_area, content_area,
                        scale_factor, canvas);
  DCHECK_GT(webkit_scale_factor, 0.0f);

  // Done printing. Close the canvas to retrieve the compiled metafile.
  if (!metafile->FinishPage())
    NOTREACHED() << "metafile failed";
}
#endif  // !defined(OS_MACOSX)

bool PrintWebViewHelper::CopyMetafileDataToSharedMem(
    const PdfMetafileSkia& metafile,
    base::SharedMemoryHandle* shared_mem_handle) {
  uint32_t buf_size = metafile.GetDataSize();
  if (buf_size == 0)
    return false;

  std::unique_ptr<base::SharedMemory> shared_buf(
      content::RenderThread::Get()->HostAllocateSharedMemoryBuffer(buf_size));
  if (!shared_buf)
    return false;

  if (!shared_buf->Map(buf_size))
    return false;

  if (!metafile.GetData(shared_buf->memory(), buf_size))
    return false;

  *shared_mem_handle =
      base::SharedMemory::DuplicateHandle(shared_buf->handle());
  return true;
}

#if BUILDFLAG(ENABLE_PRINT_PREVIEW)
void PrintWebViewHelper::ShowScriptedPrintPreview() {
  if (is_scripted_preview_delayed_) {
    is_scripted_preview_delayed_ = false;
    Send(new PrintHostMsg_ShowScriptedPrintPreview(
        routing_id(), print_preview_context_.IsModifiable()));
  }
}

void PrintWebViewHelper::RequestPrintPreview(PrintPreviewRequestType type) {
  const bool is_modifiable = print_preview_context_.IsModifiable();
  const bool has_selection = print_preview_context_.HasSelection();
  PrintHostMsg_RequestPrintPreview_Params params;
  params.is_modifiable = is_modifiable;
  params.has_selection = has_selection;
  switch (type) {
    case PRINT_PREVIEW_SCRIPTED: {
      // Shows scripted print preview in two stages.
      // 1. PrintHostMsg_SetupScriptedPrintPreview blocks this call and JS by
      //    pumping messages here.
      // 2. PrintHostMsg_ShowScriptedPrintPreview shows preview once the
      //    document has been loaded.
      is_scripted_preview_delayed_ = true;
      if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
        // Wait for DidStopLoading. Plugins may not know the correct
        // |is_modifiable| value until they are fully loaded, which occurs when
        // DidStopLoading() is called. Defer showing the preview until then.
        on_stop_loading_closure_ =
            base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
                       base::Unretained(this));
      } else {
        base::ThreadTaskRunnerHandle::Get()->PostTask(
            FROM_HERE, base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
                                  weak_ptr_factory_.GetWeakPtr()));
      }
      auto msg = base::MakeUnique<PrintHostMsg_SetupScriptedPrintPreview>(
          routing_id());
      msg->EnableMessagePumping();
      auto self = weak_ptr_factory_.GetWeakPtr();
      Send(msg.release());
      // Check if |this| is still valid.
      if (self)
        is_scripted_preview_delayed_ = false;
      return;
    }
    case PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME: {
      // Wait for DidStopLoading. Continuing with this function while
      // |is_loading_| is true will cause print preview to hang when try to
      // print a PDF document.
      if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
        on_stop_loading_closure_ =
            base::Bind(&PrintWebViewHelper::RequestPrintPreview,
                       base::Unretained(this), type);
        return;
      }

      break;
    }
    case PRINT_PREVIEW_USER_INITIATED_SELECTION: {
      DCHECK(has_selection);
      DCHECK(!GetPlugin(print_preview_context_.source_frame()));
      params.selection_only = has_selection;
      break;
    }
    case PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE: {
      if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
        on_stop_loading_closure_ =
            base::Bind(&PrintWebViewHelper::RequestPrintPreview,
                       base::Unretained(this), type);
        return;
      }

      params.webnode_only = true;
      break;
    }
    default: {
      NOTREACHED();
      return;
    }
  }
  Send(new PrintHostMsg_RequestPrintPreview(routing_id(), params));
}

bool PrintWebViewHelper::CheckForCancel() {
  const PrintMsg_Print_Params& print_params = print_pages_params_->params;
  bool cancel = false;
  Send(new PrintHostMsg_CheckForCancel(routing_id(),
                                       print_params.preview_ui_id,
                                       print_params.preview_request_id,
                                       &cancel));
  if (cancel)
    notify_browser_of_print_failure_ = false;
  return cancel;
}

bool PrintWebViewHelper::PreviewPageRendered(int page_number,
                                             PdfMetafileSkia* metafile) {
  DCHECK_GE(page_number, FIRST_PAGE_INDEX);

  // For non-modifiable files, |metafile| should be NULL, so do not bother
  // sending a message. If we don't generate draft metafiles, |metafile| is
  // NULL.
  if (!print_preview_context_.IsModifiable() ||
      !print_preview_context_.generate_draft_pages()) {
    DCHECK(!metafile);
    return true;
  }

  if (!metafile) {
    NOTREACHED();
    print_preview_context_.set_error(
        PREVIEW_ERROR_PAGE_RENDERED_WITHOUT_METAFILE);
    return false;
  }

  PrintHostMsg_DidPreviewPage_Params preview_page_params;
  // Get the size of the resulting metafile.
  if (!CopyMetafileDataToSharedMem(
          *metafile, &(preview_page_params.metafile_data_handle))) {
    LOG(ERROR) << "CopyMetafileDataToSharedMem failed";
    print_preview_context_.set_error(PREVIEW_ERROR_METAFILE_COPY_FAILED);
    return false;
  }
  preview_page_params.data_size = metafile->GetDataSize();
  preview_page_params.page_number = page_number;
  preview_page_params.preview_request_id =
      print_pages_params_->params.preview_request_id;

  Send(new PrintHostMsg_DidPreviewPage(routing_id(), preview_page_params));
  return true;
}
#endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)

PrintWebViewHelper::PrintPreviewContext::PrintPreviewContext()
    : total_page_count_(0),
      current_page_index_(0),
      generate_draft_pages_(true),
      print_ready_metafile_page_count_(0),
      error_(PREVIEW_ERROR_NONE),
      state_(UNINITIALIZED) {
}

PrintWebViewHelper::PrintPreviewContext::~PrintPreviewContext() {
}

void PrintWebViewHelper::PrintPreviewContext::InitWithFrame(
    blink::WebLocalFrame* web_frame) {
  DCHECK(web_frame);
  DCHECK(!IsRendering());
  state_ = INITIALIZED;
  source_frame_.Reset(web_frame);
  source_node_.reset();
}

void PrintWebViewHelper::PrintPreviewContext::InitWithNode(
    const blink::WebNode& web_node) {
  DCHECK(!web_node.isNull());
  DCHECK(web_node.document().frame());
  DCHECK(!IsRendering());
  state_ = INITIALIZED;
  source_frame_.Reset(web_node.document().frame());
  source_node_ = web_node;
}

void PrintWebViewHelper::PrintPreviewContext::OnPrintPreview() {
  DCHECK_EQ(INITIALIZED, state_);
  ClearContext();
}

bool PrintWebViewHelper::PrintPreviewContext::CreatePreviewDocument(
    PrepareFrameAndViewForPrint* prepared_frame,
    const std::vector<int>& pages) {
  DCHECK_EQ(INITIALIZED, state_);
  state_ = RENDERING;

  // Need to make sure old object gets destroyed first.
  prep_frame_view_.reset(prepared_frame);
  prep_frame_view_->StartPrinting();

  total_page_count_ = prep_frame_view_->GetExpectedPageCount();
  if (total_page_count_ == 0) {
    LOG(ERROR) << "CreatePreviewDocument got 0 page count";
    set_error(PREVIEW_ERROR_ZERO_PAGES);
    return false;
  }

  metafile_.reset(new PdfMetafileSkia(PDF_SKIA_DOCUMENT_TYPE));
  CHECK(metafile_->Init());

  current_page_index_ = 0;
  pages_to_render_ = pages;
  // Sort and make unique.
  std::sort(pages_to_render_.begin(), pages_to_render_.end());
  pages_to_render_.resize(
      std::unique(pages_to_render_.begin(), pages_to_render_.end()) -
      pages_to_render_.begin());
  // Remove invalid pages.
  pages_to_render_.resize(std::lower_bound(pages_to_render_.begin(),
                                           pages_to_render_.end(),
                                           total_page_count_) -
                          pages_to_render_.begin());
  print_ready_metafile_page_count_ = pages_to_render_.size();
  if (pages_to_render_.empty()) {
    print_ready_metafile_page_count_ = total_page_count_;
    // Render all pages.
    for (int i = 0; i < total_page_count_; ++i)
      pages_to_render_.push_back(i);
  } else if (generate_draft_pages_) {
    int pages_index = 0;
    for (int i = 0; i < total_page_count_; ++i) {
      if (pages_index < print_ready_metafile_page_count_ &&
          i == pages_to_render_[pages_index]) {
        pages_index++;
        continue;
      }
      pages_to_render_.push_back(i);
    }
  }

  document_render_time_ = base::TimeDelta();
  begin_time_ = base::TimeTicks::Now();

  return true;
}

void PrintWebViewHelper::PrintPreviewContext::RenderedPreviewPage(
    const base::TimeDelta& page_time) {
  DCHECK_EQ(RENDERING, state_);
  document_render_time_ += page_time;
  UMA_HISTOGRAM_TIMES("PrintPreview.RenderPDFPageTime", page_time);
}

void PrintWebViewHelper::PrintPreviewContext::AllPagesRendered() {
  DCHECK_EQ(RENDERING, state_);
  state_ = DONE;
  prep_frame_view_->FinishPrinting();
}

void PrintWebViewHelper::PrintPreviewContext::FinalizePrintReadyDocument() {
  DCHECK(IsRendering());

  base::TimeTicks begin_time = base::TimeTicks::Now();
  metafile_->FinishDocument();

  if (print_ready_metafile_page_count_ <= 0) {
    NOTREACHED();
    return;
  }

  UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderToPDFTime",
                             document_render_time_);
  base::TimeDelta total_time =
      (base::TimeTicks::Now() - begin_time) + document_render_time_;
  UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderAndGeneratePDFTime",
                             total_time);
  UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderAndGeneratePDFTimeAvgPerPage",
                             total_time / pages_to_render_.size());
}

void PrintWebViewHelper::PrintPreviewContext::Finished() {
  DCHECK_EQ(DONE, state_);
  state_ = INITIALIZED;
  ClearContext();
}

void PrintWebViewHelper::PrintPreviewContext::Failed(bool report_error) {
  DCHECK(state_ == INITIALIZED || state_ == RENDERING);
  state_ = INITIALIZED;
  if (report_error) {
    DCHECK_NE(PREVIEW_ERROR_NONE, error_);
    UMA_HISTOGRAM_ENUMERATION("PrintPreview.RendererError", error_,
                              PREVIEW_ERROR_LAST_ENUM);
  }
  ClearContext();
}

int PrintWebViewHelper::PrintPreviewContext::GetNextPageNumber() {
  DCHECK_EQ(RENDERING, state_);
  if (IsFinalPageRendered())
    return -1;
  return pages_to_render_[current_page_index_++];
}

bool PrintWebViewHelper::PrintPreviewContext::IsRendering() const {
  return state_ == RENDERING || state_ == DONE;
}

bool PrintWebViewHelper::PrintPreviewContext::IsModifiable() {
  // The only kind of node we can print right now is a PDF node.
  return !PrintingNodeOrPdfFrame(source_frame(), source_node_);
}

bool PrintWebViewHelper::PrintPreviewContext::HasSelection() {
  return IsModifiable() && source_frame()->hasSelection();
}

bool PrintWebViewHelper::PrintPreviewContext::IsLastPageOfPrintReadyMetafile()
    const {
  DCHECK(IsRendering());
  return current_page_index_ == print_ready_metafile_page_count_;
}

bool PrintWebViewHelper::PrintPreviewContext::IsFinalPageRendered() const {
  DCHECK(IsRendering());
  return static_cast<size_t>(current_page_index_) == pages_to_render_.size();
}

void PrintWebViewHelper::PrintPreviewContext::set_generate_draft_pages(
    bool generate_draft_pages) {
  DCHECK_EQ(INITIALIZED, state_);
  generate_draft_pages_ = generate_draft_pages;
}

void PrintWebViewHelper::PrintPreviewContext::set_error(
    enum PrintPreviewErrorBuckets error) {
  error_ = error;
}

blink::WebLocalFrame* PrintWebViewHelper::PrintPreviewContext::source_frame() {
  DCHECK(state_ != UNINITIALIZED);
  return source_frame_.GetFrame();
}

const blink::WebNode&
    PrintWebViewHelper::PrintPreviewContext::source_node() const {
  DCHECK(state_ != UNINITIALIZED);
  return source_node_;
}

blink::WebLocalFrame*
PrintWebViewHelper::PrintPreviewContext::prepared_frame() {
  DCHECK(state_ != UNINITIALIZED);
  return prep_frame_view_->frame();
}

const blink::WebNode&
    PrintWebViewHelper::PrintPreviewContext::prepared_node() const {
  DCHECK(state_ != UNINITIALIZED);
  return prep_frame_view_->node();
}

int PrintWebViewHelper::PrintPreviewContext::total_page_count() const {
  DCHECK(state_ != UNINITIALIZED);
  return total_page_count_;
}

bool PrintWebViewHelper::PrintPreviewContext::generate_draft_pages() const {
  return generate_draft_pages_;
}

PdfMetafileSkia* PrintWebViewHelper::PrintPreviewContext::metafile() {
  DCHECK(IsRendering());
  return metafile_.get();
}

int PrintWebViewHelper::PrintPreviewContext::last_error() const {
  return error_;
}

void PrintWebViewHelper::PrintPreviewContext::ClearContext() {
  prep_frame_view_.reset();
  metafile_.reset();
  pages_to_render_.clear();
  error_ = PREVIEW_ERROR_NONE;
}

void PrintWebViewHelper::SetPrintPagesParams(
    const PrintMsg_PrintPages_Params& settings) {
  print_pages_params_.reset(new PrintMsg_PrintPages_Params(settings));
  Send(new PrintHostMsg_DidGetDocumentCookie(routing_id(),
                                             settings.params.document_cookie));
}

PrintWebViewHelper::ScriptingThrottler::ScriptingThrottler() : count_(0) {
}

bool PrintWebViewHelper::ScriptingThrottler::IsAllowed(
    blink::WebLocalFrame* frame) {
  const int kMinSecondsToIgnoreJavascriptInitiatedPrint = 2;
  const int kMaxSecondsToIgnoreJavascriptInitiatedPrint = 32;
  bool too_frequent = false;

  // Check if there is script repeatedly trying to print and ignore it if too
  // frequent.  The first 3 times, we use a constant wait time, but if this
  // gets excessive, we switch to exponential wait time. So for a page that
  // calls print() in a loop the user will need to cancel the print dialog
  // after: [2, 2, 2, 4, 8, 16, 32, 32, ...] seconds.
  // This gives the user time to navigate from the page.
  if (count_ > 0) {
    base::TimeDelta diff = base::Time::Now() - last_print_;
    int min_wait_seconds = kMinSecondsToIgnoreJavascriptInitiatedPrint;
    if (count_ > 3) {
      min_wait_seconds =
          std::min(kMinSecondsToIgnoreJavascriptInitiatedPrint << (count_ - 3),
                   kMaxSecondsToIgnoreJavascriptInitiatedPrint);
    }
    if (diff.InSeconds() < min_wait_seconds) {
      too_frequent = true;
    }
  }

  if (!too_frequent) {
    ++count_;
    last_print_ = base::Time::Now();
    return true;
  }

  blink::WebString message(
      blink::WebString::fromUTF8("Ignoring too frequent calls to print()."));
  frame->addMessageToConsole(blink::WebConsoleMessage(
      blink::WebConsoleMessage::LevelWarning, message));
  return false;
}

void PrintWebViewHelper::ScriptingThrottler::Reset() {
  // Reset counter on successful print.
  count_ = 0;
}

}  // namespace printing