Makes GetComponentExtensionResourceManager() thread-safe.

chrome/browser/extensions/chrome_extensions_browser_client.h

 // Copyright 2013 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 CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSIONS_BROWSER_CLIENT_H_
 #define CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSIONS_BROWSER_CLIENT_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 69 matching lines @@
   void PermitExternalProtocolHandler() override;
   scoped_ptr<AppSorting> CreateAppSorting() override;
   bool IsRunningInForcedAppMode() override;
   ApiActivityMonitor* GetApiActivityMonitor(
       content::BrowserContext* context) override;
   ExtensionSystemProvider* GetExtensionSystemFactory() override;
   void RegisterExtensionFunctions(
       ExtensionFunctionRegistry* registry) const override;
   scoped_ptr<extensions::RuntimeAPIDelegate> CreateRuntimeAPIDelegate(
       content::BrowserContext* context) const override;
-  ComponentExtensionResourceManager* GetComponentExtensionResourceManager()
-      override;
+  const ComponentExtensionResourceManager*
+  GetComponentExtensionResourceManager() override;
   void BroadcastEventToRenderers(const std::string& event_name,
                                  scoped_ptr<base::ListValue> args) override;
   net::NetLog* GetNetLog() override;
   ExtensionCache* GetExtensionCache() override;
   bool IsBackgroundUpdateAllowed() override;
   bool IsMinBrowserVersionSupported(const std::string& min_version) override;
 
  private:
   friend struct base::DefaultLazyInstanceTraits<ChromeExtensionsBrowserClient>;
 
   // Observer for Chrome-specific notifications.
   ChromeNotificationObserver notification_observer_;
 
   // Support for ProcessManager.
   scoped_ptr<ChromeProcessManagerDelegate> process_manager_delegate_;
 
   // Client for API implementations.
   scoped_ptr<ChromeExtensionsAPIClient> api_client_;
 
   scoped_ptr<ChromeComponentExtensionResourceManager> resource_manager_;
 
   scoped_ptr<ExtensionCache> extension_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeExtensionsBrowserClient);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSIONS_BROWSER_CLIENT_H_