Mac a11y: Add Help, TopLevelUIElement, and Window accessibility attributes.

ui/views/accessibility/native_view_accessibility.h

 // Copyright (c) 2013 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_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_H_
 #define UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_H_
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "ui/accessibility/ax_node_data.h"
@@ skipping 31 matching lines @@
   // Call Destroy rather than deleting this, because the subclass may
   // use reference counting.
   virtual void Destroy();
 
   void NotifyAccessibilityEvent(ui::AXEvent event_type);
 
   // ui::AXPlatformNodeDelegate
   const ui::AXNodeData& GetData() override;
   int GetChildCount() override;
   gfx::NativeViewAccessible ChildAtIndex(int index) override;
+  gfx::NativeWindow GetTopLevelWidget() override;
   gfx::NativeViewAccessible GetParent() override;
   gfx::Vector2d GetGlobalCoordinateOffset() override;
   gfx::NativeViewAccessible HitTestSync(int x, int y) override;
   gfx::NativeViewAccessible GetFocus() override;
   gfx::AcceleratedWidget GetTargetForNativeAccessibilityEvent() override;
   void DoDefaultAction() override;
   bool SetStringValue(const base::string16& new_value) override;
 
   // WidgetObserver
   void OnWidgetDestroying(Widget* widget) override;
@@ skipping 21 matching lines @@
   ui::AXPlatformNode* ax_node_;
 
   ui::AXNodeData data_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeViewAccessibility);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_H_