Disable accessibility when VoiceOver is turned off.

content/renderer/accessibility/renderer_accessibility.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 CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_H_
 #define CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_H_
 
 #include "content/common/accessibility_messages.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "third_party/WebKit/public/web/WebAXObject.h"
@@ skipping 42 matching lines @@
 
   // Called when an accessibility notification occurs in Blink.
   virtual void HandleWebAccessibilityEvent(
       const blink::WebAXObject& obj, blink::WebAXEvent event) = 0;
   virtual void FocusedNodeChanged(const blink::WebNode& node) = 0;
 
   // Gets the type of this RendererAccessibility object. Primarily intended for
   // testing.
   virtual RendererAccessibilityType GetType() = 0;
 
+  // This can be called before deleting a RendererAccessibility instance due
+  // to the accessibility mode changing, as opposed to during frame destruction
+  // (when there'd be no point).
+  virtual void DisableAccessibility() {}
+
  protected:
   // Returns the main top-level document for this page, or NULL if there's
   // no view or frame.
   blink::WebDocument GetMainDocument();
 
   // The RenderFrameImpl that owns us.
   RenderFrameImpl* render_frame_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererAccessibility);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_H_