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

chrome/browser/renderer_host/resource_dispatcher_host.cc

 // 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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 
 #include <vector>
 
@@ skipping 460 matching lines @@
     request->set_upload(request_data.upload_data);
     upload_size = request_data.upload_data->GetContentLength();
   }
 
   // Install a CrossSiteResourceHandler if this request is coming from a
   // RenderViewHost with a pending cross-site request.  We only check this for
   // MAIN_FRAME requests. Unblock requests only come from a blocked page, do
   // not count as cross-site, otherwise it gets blocked indefinitely.
   if (request_data.resource_type == ResourceType::MAIN_FRAME &&
       process_type == ChildProcessInfo::RENDER_PROCESS &&
-      Singleton<CrossSiteRequestManager>::get()->
+      CrossSiteRequestManager::GetInstance()->
           HasPendingCrossSiteRequest(child_id, route_id)) {
     // Wrap the event handler to be sure the current page's onunload handler
     // has a chance to run before we render the new page.
     handler = new CrossSiteResourceHandler(handler,
                                            child_id,
                                            route_id,
                                            this);
   }
 
   // Insert a buffered event handler before the actual one.
@@ skipping 1468 matching lines @@
   return is_prefetch_enabled_;
 }
 
 // static
 void ResourceDispatcherHost::set_is_prefetch_enabled(bool value) {
   is_prefetch_enabled_ = value;
 }
 
 // static
 bool ResourceDispatcherHost::is_prefetch_enabled_ = false;