Added a class acting as a fake caret for accessibility.

ui/accessibility/platform/ax_fake_caret_win.h

+// Copyright 2017 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 UI_ACCESSIBILITY_PLATFORM_AX_FAKE_CARET_WIN_H_
+#define UI_ACCESSIBILITY_PLATFORM_AX_FAKE_CARET_WIN_H_
+
+#include <oleacc.h>
+
+#include "base/macros.h"
+#include "base/win/scoped_comptr.h"
+#include "ui/accessibility/ax_export.h"
+#include "ui/accessibility/ax_node_data.h"
+#include "ui/accessibility/platform/ax_platform_node_delegate.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/native_widget_types.h"
+
+namespace ui {
+
+class AXPlatformNodeWin;
+
+// A class representing the position of the caret to assistive software on
+// Windows. This is required because Chrome doesn't use the standard system
+// caret and because some assistive software still relies on specific
+// accessibility APIs to retrieve the caret position.
+class AX_EXPORT AXFakeCaretWin : private AXPlatformNodeDelegate {
+ public:
+  AXFakeCaretWin(gfx::AcceleratedWidget event_target);
+  virtual ~AXFakeCaretWin();
+
+  base::win::ScopedComPtr<IAccessible> GetCaret() const;
+  void MoveCaretTo(const gfx::Rect& bounds);
+
+ private:
+  // |AXPlatformNodeDelegate| members.
+  const AXNodeData& GetData() const override;
+  gfx::NativeWindow GetTopLevelWidget() override;
+  gfx::NativeViewAccessible GetParent() override;
+  int GetChildCount() override;
+  gfx::NativeViewAccessible ChildAtIndex(int index) override;
+  gfx::Rect GetScreenBoundsRect() const override;
+  gfx::NativeViewAccessible HitTestSync(int x, int y) override;
+  gfx::NativeViewAccessible GetFocus() override;
+  gfx::AcceleratedWidget GetTargetForNativeAccessibilityEvent() override;
+  bool AccessibilityPerformAction(const ui::AXActionData& data) override;
+
+  AXPlatformNodeWin* caret_;
+  gfx::AcceleratedWidget event_target_;
+  AXNodeData data_;
+
+  friend class AXPlatformNodeWin;
+  DISALLOW_COPY_AND_ASSIGN(AXFakeCaretWin);
+};
+
+}  // namespace ui
+
+#endif  // UI_ACCESSIBILITY_PLATFORM_AX_FAKE_CARET_WIN_H_