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// Copyright 2016 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.
#ifndef TopDocumentRootScrollerController_h
#define TopDocumentRootScrollerController_h
#include "core/CoreExport.h"
#include "core/page/scrolling/RootScrollerController.h"
#include "platform/geometry/IntSize.h"
#include "platform/heap/Handle.h"
namespace blink {
class Element;
class FrameHost;
class GraphicsLayer;
class PaintLayer;
class RootFrameViewport;
class ScrollStateCallback;
class ScrollableArea;
class ViewportScrollCallback;
// This class manages the the page level aspects of the root scroller. That
// is, given all the iframes on a page and their individual root scrollers,
// this class will determine which ultimate Element should be used as the root
// scroller and ensures that Element is used to scroll browser controls and
// provide overscroll effects.
// TODO(bokan): This class is currently OOPIF unaware. crbug.com/642378.
class CORE_EXPORT TopDocumentRootScrollerController
: public GarbageCollected<TopDocumentRootScrollerController> {
public:
static TopDocumentRootScrollerController* create(FrameHost&);
DECLARE_TRACE();
// This class needs to be informed of changes to compositing so that it can
// update the compositor when the effective root scroller changes.
void didUpdateCompositing();
// PaintLayerScrollableAreas need to notify this class when they're being
// disposed so that we can remove them as the root scroller.
void didDisposeScrollableArea(ScrollableArea&);
// This method needs to be called to create a ViewportScrollCallback that
// will be used to apply viewport scrolling actions like browser controls
// movement and overscroll glow.
void initializeViewportScrollCallback(RootFrameViewport&);
// Returns true if the given ScrollStateCallback is the
// ViewportScrollCallback managed by this class.
// TODO(bokan): Temporarily needed to allow ScrollCustomization to
// differentiate between real custom callback and the built-in viewport
// apply scroll. crbug.com/623079.
bool isViewportScrollCallback(const ScrollStateCallback*) const;
// Returns the GraphicsLayer for the global root scroller.
GraphicsLayer* rootScrollerLayer() const;
PaintLayer* rootScrollerPaintLayer() const;
// Returns the Element that's the global root scroller.
Element* globalRootScroller() const;
// Called when the root scroller in any frames on the page has changed.
void didChangeRootScroller();
void mainFrameViewResized();
// Returns the ScrollableArea associated with the globalRootScroller(). Note,
// this isn't necessarily the PLSA belonging to the root scroller Element's
// LayoutBox. If the root scroller is the documentElement then we use the
// FrameView (or LayoutView if root-layer-scrolls).
ScrollableArea* rootScrollerArea() const;
// Returns the size we should use for the root scroller, accounting for top
// controls adjustment and using the root FrameView.
IntSize rootScrollerVisibleArea() const;
private:
TopDocumentRootScrollerController(FrameHost&);
// Calculates the Element that should be the globalRootScroller. On a
// simple page, this will simply the root frame's effectiveRootScroller but
// if the root scroller is set to an iframe, this will then descend into
// the iframe to find its effective root scroller.
Element* findGlobalRootScrollerElement();
// Should be called to ensure the correct element is currently set as the
// global root scroller and that all appropriate state changes are made if
// it changes.
void recomputeGlobalRootScroller();
Document* topDocument() const;
void setNeedsCompositingInputsUpdateOnGlobalRootScroller();
// The apply-scroll callback that moves browser controls and produces
// overscroll effects. This class makes sure this callback is set on the
// appropriate root scroller element.
Member<ViewportScrollCallback> m_viewportApplyScroll;
// The page level root scroller. i.e. The actual element for which
// scrolling should move browser controls and produce overscroll glow. Once an
// m_viewportApplyScroll has been created, it will always be set on this
// Element.
WeakMember<Element> m_globalRootScroller;
WeakMember<FrameHost> m_frameHost;
};
} // namespace blink
#endif // RootScrollerController_h
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