Invalidate the previous frame when the window object is cleared.

content/public/renderer/render_view_observer.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_PUBLIC_RENDERER_RENDER_VIEW_OBSERVER_H_
 #define CONTENT_PUBLIC_RENDERER_RENDER_VIEW_OBSERVER_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
+#include "v8/include/v8.h"
 
 class GURL;
 
 namespace ppapi {
 namespace host {
 class PpapiHost;
 }
 }
 
 namespace blink {
@@ skipping 46 matching lines @@
   virtual void DidMatchCSS(
       blink::WebLocalFrame* frame,
       const blink::WebVector<blink::WebString>& newly_matching_selectors,
       const blink::WebVector<blink::WebString>& stopped_matching_selectors) {}
   virtual void WillSendSubmitEvent(blink::WebLocalFrame* frame,
                                    const blink::WebFormElement& form) {}
   virtual void WillSubmitForm(blink::WebLocalFrame* frame,
                               const blink::WebFormElement& form) {}
   virtual void DidCreateDataSource(blink::WebLocalFrame* frame,
                                    blink::WebDataSource* ds) {}
+  virtual void WillReleaseScriptContext(blink::WebLocalFrame* frame,
+                                        v8::Handle<v8::Context> context,
+                                        int world_id) {}
   virtual void PrintPage(blink::WebLocalFrame* frame, bool user_initiated) {}
   virtual void FocusedNodeChanged(const blink::WebNode& node) {}
   virtual void DidChangeScrollOffset(blink::WebLocalFrame* frame) {}
   virtual void DraggableRegionsChanged(blink::WebFrame* frame) {}
   virtual void DidCommitCompositorFrame() {}
   virtual void DidUpdateLayout() {}
 
   // These match the RenderView methods.
   virtual void DidHandleMouseEvent(const blink::WebMouseEvent& event) {}
   virtual void DidHandleTouchEvent(const blink::WebTouchEvent& event) {}
@@ skipping 36 matching lines @@
   RenderView* render_view_;
   // The routing ID of the associated RenderView.
   int routing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_RENDER_VIEW_OBSERVER_H_