Add a new GetInstance() method for singleton classes used in chrome/browser files.

chrome/browser/dom_ui/chrome_url_data_manager.h

 // Copyright (c) 2010 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_DOM_UI_CHROME_URL_DATA_MANAGER_H_
 #define CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H_
 #pragma once
 
 #include <map>
 #include <string>
 
+#include "base/singleton.h"
 #include "base/task.h"
 #include "base/ref_counted.h"
 
 class DictionaryValue;
 class FilePath;
 class GURL;
 class MessageLoop;
 class RefCountedMemory;
 class URLRequestChromeJob;
 
 namespace net {
 class URLRequest;
 class URLRequestJob;
 }  // namespace net
 
 // To serve dynamic data off of chrome: URLs, implement the
 // ChromeURLDataManager::DataSource interface and register your handler
 // with AddDataSource.
 
 // ChromeURLDataManager lives on the IO thread, so any interfacing with
 // it from the UI thread needs to go through an InvokeLater.
 class ChromeURLDataManager {
  public:
-  ChromeURLDataManager();
-  ~ChromeURLDataManager();
+  // Returns the singleton instance.
+  static ChromeURLDataManager* GetInstance();
 
   typedef int RequestID;
 
   // A DataSource is an object that can answer requests for data
   // asynchronously. DataSources are collectively owned with refcounting smart
   // pointers and should never be deleted on the IO thread, since their calls
   // are handled almost always on the UI thread and there's a possibility of a
   // data race.
   //
   // An implementation of DataSource should handle calls to
@@ skipping 68 matching lines @@
   // Calling this from threads other the IO thread must be done via
   // InvokeLater.
   void AddFileSource(const std::string& source_name, const FilePath& path);
   void RemoveFileSource(const std::string& source_name);
 
   static net::URLRequestJob* Factory(net::URLRequest* request,
                                      const std::string& scheme);
 
  private:
   friend class URLRequestChromeJob;
+  friend struct DefaultSingletonTraits<ChromeURLDataManager>;
+
+  ChromeURLDataManager();
+  ~ChromeURLDataManager();
 
   // Parse a URL into the components used to resolve its request.
   static void URLToRequest(const GURL& url,
                            std::string* source,
                            std::string* path);
 
   // Translate a chrome resource URL into a local file path if there is one.
   // Returns false if there is no file handler for this URL
   static bool URLToFilePath(const GURL& url, FilePath* file_path);
 
@@ skipping 35 matching lines @@
 DISABLE_RUNNABLE_METHOD_REFCOUNT(ChromeURLDataManager);
 
 // Register our special URL handler under our special URL scheme.
 // Must be done once at startup.
 void RegisterURLRequestChromeJob();
 
 // Undoes the registration done by RegisterURLRequestChromeJob.
 void UnregisterURLRequestChromeJob();
 
 #endif  // CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H_