Revert of Stop copying script contents for each RenderFrames.

extensions/renderer/user_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_USER_SCRIPT_INJECTOR_H_
 #define EXTENSIONS_RENDERER_USER_SCRIPT_INJECTOR_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 45 matching lines @@
   void OnInjectionComplete(std::unique_ptr<base::Value> execution_result,
                            UserScript::RunLocation run_location,
                            content::RenderFrame* render_frame) override;
   void OnWillNotInject(InjectFailureReason reason,
                        content::RenderFrame* render_frame) override;
 
   // The associated user script. Owned by the UserScriptInjector that created
   // this object.
   const UserScript* script_;
 
-  // The UserScriptSet that eventually owns the UserScript this
-  // UserScriptInjector points to.
-  // Outlives |this|.
-  UserScriptSet* const user_script_set_;
-
   // The id of the associated user script. We cache this because when we update
   // the |script_| associated with this injection, the old referance may be
   // deleted.
   int script_id_;
 
   // The associated host id, preserved for the same reason as |script_id|.
   HostID host_id_;
 
   // Indicates whether or not this script is declarative. This influences which
   // script permissions are checked before injection.
   bool is_declarative_;
 
   ScopedObserver<UserScriptSet, UserScriptSet::Observer>
       user_script_set_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptInjector);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_USER_SCRIPT_INJECTOR_H_