Reland: Add an event to notify accessibility when a permissions bubble gets shown.

ui/views/bubble/bubble_delegate.h

 // 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.
 
 #ifndef UI_VIEWS_BUBBLE_BUBBLE_DELEGATE_H_
 #define UI_VIEWS_BUBBLE_BUBBLE_DELEGATE_H_
 
 #include "base/gtest_prod_util.h"
 #include "ui/views/bubble/bubble_border.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/widget/widget_observer.h"
 
 namespace gfx {
 class FontList;
 class Rect;
 }
 
 namespace views {
 
 class BubbleFrameView;
 
 // BubbleDelegateView creates frame and client views for bubble Widgets.
 // BubbleDelegateView itself is the client's contents view.
+// Note for those adding subclasses, to have your view read in its entirety by

[msw, 2015/04/07 21:36:06]

You can leave this comment with the NotifyAccessibilityEvent block in the
HandleVisibilityChanged impl. Consider rephrasing the comment to something like:
"Fire AX_EVENT_ALERT for bubbles marked as AX_ROLE_ALERT_DIALOG; this instructs
accessibility tools to read the bubble in its entirety, rather than just its
title and initially focused view. See http://crbug.com/474622 for details."

[David Tseng, 2015/04/07 21:50:53]

Done.

+// accessibility tools, set your view to ui::AX_ROLE_ALERT_DIALOG. See
+//http://crbug.com/474622 for further context.
 class VIEWS_EXPORT BubbleDelegateView : public WidgetDelegateView,
                                         public WidgetObserver {
  public:
   // Internal class name.
   static const char kViewClassName[];
 
   BubbleDelegateView();
   BubbleDelegateView(View* anchor_view, BubbleBorder::Arrow arrow);
   ~BubbleDelegateView() override;
 
@@ skipping 156 matching lines @@
 
   // Parent native window of the bubble.
   gfx::NativeView parent_window_;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleDelegateView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_BUBBLE_BUBBLE_DELEGATE_H_