A11y: Add/refactor methods for manipulating bitfields on AXNodeData.

ui/views/bubble/bubble_dialog_delegate.cc

 // Copyright 2016 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_dialog_delegate.h"
 
 #include "build/build_config.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/base/default_style.h"
 #include "ui/base/material_design/material_design_controller.h"
@@ skipping 302 matching lines @@
       anchor_widget()->GetTopLevelWidget()) {
     anchor_widget()->GetTopLevelWidget()->SetAlwaysRenderAsActive(visible);
   }
 
   // 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.
   if (widget == GetWidget() && visible) {
     ui::AXNodeData node_data;
+    node_data.ClearBitfields();
     GetAccessibleNodeData(&node_data);
     if (node_data.role == ui::AX_ROLE_ALERT_DIALOG)
       NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
   }
 }
 
 }  // namespace views