Fire an alert event to notify accessibility when a permissions bubble gets shown.

ui/views/bubble/bubble_delegate.cc

 // 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.
 
 #include "ui/views/bubble/bubble_delegate.h"
 
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/geometry/rect.h"
@@ skipping 282 matching lines @@
     color_ = theme->GetSystemColor(ui::NativeTheme::kColorId_DialogBackground);
   set_background(Background::CreateSolidBackground(color()));
   BubbleFrameView* frame_view = GetBubbleFrameView();
   if (frame_view)
     frame_view->bubble_border()->set_background_color(color());
 }
 
 void BubbleDelegateView::HandleVisibilityChanged(Widget* widget, bool visible) {
   if (widget == GetWidget() && anchor_widget() &&
       anchor_widget()->GetTopLevelWidget()) {
-    if (visible)
+    if (visible) {
       anchor_widget()->GetTopLevelWidget()->DisableInactiveRendering();
-    else
+      NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);

[msw, 2015/04/06 17:30:19]

Most bubbles should have an anchor, but I suspect that firing this event
shouldn't be contingent on the presence of an anchor widget (nor that object's
top level widget).

[David Tseng, 2015/04/06 17:36:05]

Done.

+    } else {
       anchor_widget()->GetTopLevelWidget()->EnableInactiveRendering();
+    }
   }
 }
 
 }  // namespace views