[Extensions] Don't allow extensions to inject scripts into extension pages

extensions/renderer/user_script_set.cc

 // 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.
 
 #include "extensions/renderer/user_script_set.h"
 
 #include "base/memory/ref_counted.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_thread.h"
@@ skipping 193 matching lines @@
   if (!script->MatchesURL(effective_document_url))
     return injection.Pass();
 
   scoped_ptr<ScriptInjector> injector(new UserScriptInjector(script,
                                                              this,
                                                              is_declarative));
 
   if (injector->CanExecuteOnFrame(
           injection_host.get(),
           web_frame,
-          -1 /* Content scripts are not tab-specific. */) ==
+          tab_id) ==
       PermissionsData::ACCESS_DENIED) {
     return injection.Pass();
   }
 
   bool inject_css = !script->css_scripts().empty() &&
                     run_location == UserScript::DOCUMENT_START;
   bool inject_js =
       !script->js_scripts().empty() && script->run_location() == run_location;
   if (inject_css || inject_js) {
     injection.reset(new ScriptInjection(
         injector.Pass(),
         render_frame,
         injection_host.Pass(),
-        run_location,
-        tab_id));
+        run_location));
   }
   return injection.Pass();
 }
 
 }  // namespace extensions