Reimplement web content accessibility by caching in browser process

chrome/browser/renderer_host/render_widget_host_view.h

Index: chrome/browser/renderer_host/render_widget_host_view.h
===================================================================
--- chrome/browser/renderer_host/render_widget_host_view.h	(revision 46908)
+++ chrome/browser/renderer_host/render_widget_host_view.h	(working copy)
@@ -15,6 +15,7 @@
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebPopupType.h"
 #include "webkit/glue/plugins/webplugin.h"
+#include "webkit/glue/webaccessibility.h"
 
 namespace gfx {
 class Rect;
@@ -235,6 +236,11 @@
   // widget associated with this RenderWidgetHostView.
   virtual bool ContainsNativeView(gfx::NativeView native_view) const = 0;
 
+  virtual void UpdateAccessibilityTree(
+      const webkit_glue::WebAccessibility& tree) { }
+  virtual void OnAccessibilityFocusChange(int acc_obj_id) { }
+  virtual void OnAccessibilityObjectStateChange(int acc_obj_id) { }
+
  protected:
   // Interface class only, do not construct.
   RenderWidgetHostView() : popup_type_(WebKit::WebPopupTypeNone) {}