1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_TREE_MANAGER_DELEGATE_H_
#define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_TREE_MANAGER_DELEGATE_H_
#include "base/component_export.h"
#include "base/functional/callback_forward.h"
#include "ui/accessibility/ax_action_data.h"
#include "ui/accessibility/ax_enums.mojom-forward.h"
#include "ui/accessibility/ax_node_id_forward.h"
#include "ui/accessibility/platform/ax_platform_node_id.h"
#include "ui/accessibility/platform/ax_platform_tree_manager.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/native_widget_types.h"
namespace content {
class WebContentsAccessibility;
}
namespace ui {
// Pure abstract class that is used by `AXPlatformTreeManager` to gather
// information or perform actions that are implemented differently between the
// Web Content and the Views layers.
//
// TODO(nektar): Change `AXPlatformTreeManager` to take this delegate in its
// constructor and store it as a member variable.
class COMPONENT_EXPORT(AX_PLATFORM) AXPlatformTreeManagerDelegate {
public:
virtual ~AXPlatformTreeManagerDelegate() = default;
AXPlatformTreeManagerDelegate(const AXPlatformTreeManagerDelegate&) = delete;
AXPlatformTreeManagerDelegate& operator=(
const AXPlatformTreeManagerDelegate&) = delete;
// Carries out an action on a specific UI element as requested by an assistive
// software, such as opening the context menu or setting the value of a text
// field. In this context, a "UI element" is represented by an `AXNodeID`,
// i.e. the ID of a node in an accessibility tree.
//
// Note that even though such actions are programmatically requested, they
// should be performed as if the user has initiated them, since the assistive
// software is (directly or indirectly) acting on behalf of the user.
virtual void AccessibilityPerformAction(const AXActionData& data) = 0;
// Returns true if the `View` that contains the current accessibility tree is
// focused. Example: the `content::RenderWidgetHostView` exposing the current
// accessibility tree.
//
// Note that when accessibility is turned on, focus might behave differently,
// including making some unfocusable UI elements to become focusable. See
// `views::FocusBehavior`.
virtual bool AccessibilityViewHasFocus() = 0;
// Moves the focus inside the View` that contains the current accessibility
// tree, Example: the `content::RenderWidgetHostView` exposing the current
// accessibility tree.
//
// Note that when accessibility is turned on, focus might behave differently,
// including making some unfocusable UI elements to become focusable. See
// `views::FocusBehavior`.
virtual void AccessibilityViewSetFocus() = 0;
// Returns the bounds (in screen coordinates) of the `View` that contains the
// current accessibility tree, Example: the `content::RenderWidgetHostView`
// exposing the current accessibility tree.
virtual gfx::Rect AccessibilityGetViewBounds() = 0;
// Returns the multiplication factor by which the sizes of UI elements need to
// be adjusted. In most cases this is 1.0F, however on some platforms element
// sizes are not adjusted at the accessibility tree source, such as in Blink.
virtual float AccessibilityGetDeviceScaleFactor() = 0;
// The accessibility tree source has sent us invalid information. This could
// indicate either a serious error or a malicious attack, e.g. from a rogue
// renderer.
virtual void UnrecoverableAccessibilityError() = 0;
// Returns a handle to the platform specific widget containing the current
// accessibility tree. Example: the HWND of the widget containing the
// currently displayed web contents on Windows.
virtual gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget() = 0;
// Returns a pointer to the platform specific accessibility object containing
// the current accessibility tree. Example: a pointer to a Cocoa object
// conforming to the `NSAccessibility` protocol on macOS.
virtual gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() = 0;
// Same as above but for the current window, e.g. the currently focused
// `NSWindow` object on macOS.
virtual gfx::NativeViewAccessible
AccessibilityGetNativeViewAccessibleForWindow() = 0;
// Determines the node, together with its corresponding accessibility tree,
// that is located at a specific point in the current tree's coordinates, i.e.
// assumes that the current tree's root is located at (0, 0). Note that
// multiple child trees could be contained within the current accessibility
// tree, for example the accessibility tree for a webpage could contain
// multiple child trees representing remote iframes.
//
// Note that hit testing in the Web layer needs to send a message via
// inter-process communication to Blink in order to get back an accurate
// response, which may depend on the interaction among various CSS rules. In
// the Views layer, there is no such requirement, and thus a much simpler
// implementation of "hit testing" could be provided.
//
// TODO(nektar): Use `std::optional` for all optional arguments.
virtual void AccessibilityHitTest(
const gfx::Point& point_in_view_pixels,
const ax::mojom::Event& opt_event_to_fire,
int opt_request_id,
base::OnceCallback<void(AXPlatformTreeManager* hit_manager,
AXNodeID hit_node_id)> opt_callback) = 0;
virtual gfx::NativeWindow GetTopLevelNativeWindow() = 0;
virtual bool CanFireAccessibilityEvents() const = 0;
// These methods are all specific to Web content, and should be removed from
// here and into the content layer if and when possible. These were
// moved into AXPlatformTreeManagerDelegate as part of the refactor
// to move BrowserAccessibility* into the ui/ layer to support their reuse
// in views. crbug.com/327499435
virtual bool AccessibilityIsRootFrame() const = 0;
// On Mac, VoiceOver moves focus to the web content when it receives an
// AXLoadComplete event. On chrome's new tab page, focus should stay
// in the omnibox, so we purposefully do not fire the AXLoadComplete
// event in this case.
virtual bool ShouldSuppressAXLoadComplete() = 0;
virtual content::WebContentsAccessibility*
AccessibilityGetWebContentsAccessibility() = 0;
// Returns true if the current accessibility tree is for web content, false if
// it's for Views.
virtual bool AccessibilityIsWebContentSource() = 0;
protected:
AXPlatformTreeManagerDelegate() = default;
};
} // namespace ui
#endif // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_TREE_MANAGER_DELEGATE_H_
|
