Improve error message for failing code insertion on about:-URLs

extensions/renderer/programmatic_script_injector.h

 // Copyright 2014 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 EXTENSIONS_RENDERER_PROGRAMMATIC_SCRIPT_INJECTOR_H_
 #define EXTENSIONS_RENDERER_PROGRAMMATIC_SCRIPT_INJECTOR_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "extensions/renderer/script_injection.h"
@@ skipping 47 matching lines @@
   // Notify the browser that the script was injected (or never will be), and
   // send along any results or errors.
   void Finish(const std::string& error);
 
   // The parameters for injecting the script.
   scoped_ptr<ExtensionMsg_ExecuteCode_Params> params_;
 
   // The url of the frame into which we are injecting.
   GURL url_;
 
+  // The URL of the frame's origin. This is usually identical to |url_|, but
+  // could be different for e.g. about:blank URLs. Do not use this value to make
+  // security decisions, to avoid race conditions (e.g. due to navigation).
+  GURL effective_url_;
+
   // The RenderView to which we send the response upon completion.
   content::RenderView* render_view_;
 
   // The results of the script execution.
   scoped_ptr<base::ListValue> results_;
 
   // Whether or not this script injection has finished.
   bool finished_;
 
   DISALLOW_COPY_AND_ASSIGN(ProgrammaticScriptInjector);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_PROGRAMMATIC_SCRIPT_INJECTOR_H_