Get rid of RequestRegistry (part 5): each request cancels itself.

chrome/browser/google_apis/request_sender.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/google_apis/request_sender.h"
 
 #include "base/bind.h"
 #include "chrome/browser/google_apis/auth_service.h"
 #include "chrome/browser/google_apis/base_requests.h"
 
@@ skipping 75 matching lines @@
   StartRequestWithRetry(request);
 }
 
 void RequestSender::CancelRequest(
     const base::WeakPtr<AuthenticatedRequestInterface>& request) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Do nothing if the request is already finished.
   if (!request.get())
     return;
-  request_registry_->CancelRequest(request->AsRequestRegistryRequest());
+  request->Cancel();
 }
 
 }  // namespace google_apis