Remove some unused cloud print histograms.

chrome/service/service_utility_process_host.h

 // 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.
 
 #ifndef CHROME_SERVICE_SERVICE_UTILITY_PROCESS_HOST_H_
 #define CHROME_SERVICE_SERVICE_UTILITY_PROCESS_HOST_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 132 matching lines @@
       const std::string& printer_name);
 
   std::unique_ptr<content::ChildProcessHost> child_process_host_;
   base::Process process_;
   // A pointer to our client interface, who will be informed of progress.
   scoped_refptr<Client> client_;
   scoped_refptr<base::SingleThreadTaskRunner> client_task_runner_;
   bool waiting_for_reply_;
   mojo::edk::PendingProcessConnection process_connection_;
 
-  // Start time of operation.
-  base::Time start_time_;
-
   class PdfToEmfState;
   std::unique_ptr<PdfToEmfState> pdf_to_emf_state_;
 
   base::WeakPtrFactory<ServiceUtilityProcessHost> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceUtilityProcessHost);
 };
 
 #endif  // CHROME_SERVICE_SERVICE_UTILITY_PROCESS_HOST_H_