GCM Engine: Split up reg/unreg UNKNOWN_ERROR to improve metrics

google_apis/gcm/engine/instance_id_delete_token_request_handler.h

 // Copyright 2015 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 GOOGLE_APIS_GCM_ENGINE_INSTANCE_ID_DELETE_TOKEN_REQUEST_HANDLER_H_
 #define GOOGLE_APIS_GCM_ENGINE_INSTANCE_ID_DELETE_TOKEN_REQUEST_HANDLER_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "google_apis/gcm/engine/unregistration_request.h"
 
 namespace gcm {
 
 // Provides custom logic to handle DeleteToken request for InstanceID.
 class GCM_EXPORT InstanceIDDeleteTokenRequestHandler :
   public UnregistrationRequest::CustomRequestHandler {
  public:
   InstanceIDDeleteTokenRequestHandler(
       const std::string& instance_id,
       const std::string& authorized_entity,
       const std::string& scope,
       int gcm_version);
   ~InstanceIDDeleteTokenRequestHandler() override;
 
    // UnregistrationRequest overrides:
   void BuildRequestBody(std::string* body) override;
   UnregistrationRequest::Status ParseResponse(
-      const net::URLFetcher* source) override;
+      const std::string& response) override;
   void ReportUMAs(UnregistrationRequest::Status status,
                   int retry_count,
                   base::TimeDelta complete_time) override;
 
  private:
   std::string instance_id_;
   std::string authorized_entity_;
   std::string scope_;
   int gcm_version_;
 
   DISALLOW_COPY_AND_ASSIGN(InstanceIDDeleteTokenRequestHandler);
 };
 
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_ENGINE_INSTANCE_ID_DELETE_TOKEN_REQUEST_HANDLER_H_