Create thread-safe RendererExtensionRegistry from ExtensionSet

extensions/renderer/dispatcher.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_DISPATCHER_H_
 #define EXTENSIONS_RENDERER_DISPATCHER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 56 matching lines @@
 class Dispatcher : public content::RenderProcessObserver,
                    public UserScriptSetManager::Observer {
  public:
   explicit Dispatcher(DispatcherDelegate* delegate);
   ~Dispatcher() override;
 
   const std::set<std::string>& function_names() const {
     return function_names_;
   }
 
-  const ExtensionSet* extensions() const { return &extensions_; }
+  const ExtensionSet* extensions() const;
 
   const ScriptContextSet& script_context_set() const {
     return *script_context_set_;
   }
 
   V8SchemaRegistry* v8_schema_registry() { return v8_schema_registry_.get(); }
 
   ContentWatcher* content_watcher() { return content_watcher_.get(); }
 
   RequestSender* request_sender() { return request_sender_.get(); }
@@ skipping 161 matching lines @@
   // Adds features that are specific to the current channel.
   void AddChannelSpecificFeatures();
 
   // The delegate for this dispatcher. Not owned, but must extend beyond the
   // Dispatcher's own lifetime.
   DispatcherDelegate* delegate_;
 
   // True if the IdleNotification timer should be set.
   bool set_idle_notifications_;
 
-  // Contains all loaded extensions.  This is essentially the renderer
-  // counterpart to ExtensionService in the browser. It contains information
-  // about all extensions currently loaded by the browser.
-  ExtensionSet extensions_;
-
   // The IDs of extensions that failed to load, mapped to the error message
   // generated on failure.
   std::map<std::string, std::string> extension_load_errors_;
 
   // All the bindings contexts that are currently loaded for this renderer.
   // There is zero or one for each v8 context.
   scoped_ptr<ScriptContextSet> script_context_set_;
 
   scoped_ptr<ContentWatcher> content_watcher_;
 
@@ skipping 36 matching lines @@
 
   // Status of webrequest usage.
   bool webrequest_used_;
 
   DISALLOW_COPY_AND_ASSIGN(Dispatcher);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_DISPATCHER_H_