Deal with frame removal by content scripts

extensions/renderer/dispatcher.h

Index: extensions/renderer/dispatcher.h
diff --git a/extensions/renderer/dispatcher.h b/extensions/renderer/dispatcher.h
index 40194a06d2ab6a40e83b300a226098bcbfb8aa26..eb4372cc0c778f6e345c76eae40423d63da83370 100644
--- a/extensions/renderer/dispatcher.h
+++ b/extensions/renderer/dispatcher.h
@@ -108,8 +108,14 @@ class Dispatcher : public content::RenderProcessObserver,
       v8::Local<v8::Context> v8_context,
       const GURL& url);
 
+  // This method is not allowed to run JavaScript code in the frame.
   void DidCreateDocumentElement(blink::WebLocalFrame* frame);
 
+  // These methods may run (untrusted) JavaScript code in the frame, and
+  // cause |render_frame| to become invalid.
+  void RunScriptsAtDocumentStart(content::RenderFrame* render_frame);
+  void RunScriptsAtDocumentEnd(content::RenderFrame* render_frame);
+
   void OnExtensionResponse(int request_id,
                            bool success,
                            const base::ListValue& response,