Atomic UserScript ID generation

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 <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 48 matching lines @@
       UserScript::RunLocation run_location) OVERRIDE;
   virtual void OnWillNotInject(InjectFailureReason reason) OVERRIDE;
 
   // The associated user script. Owned by the UserScriptInjector that created
   // this object.
   const UserScript* script_;
 
   // 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.
-  int64 script_id_;
+  int script_id_;
 
   // The associated extension id, preserved for the same reason as |script_id|.
   std::string extension_id_;
 
   ScopedObserver<UserScriptSet, UserScriptSet::Observer>
       user_script_set_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptInjector);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_USER_SCRIPT_INJECTOR_H_