Decouple Metrics Initialization from IO Thread Initialization

chrome/browser/browser_process_impl.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/browser_process_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 1050 matching lines @@
   io_thread_.reset(
       new IOThread(local_state(), policy_service(), net_log_.get(),
                    extension_event_router_forwarder()));
 }
 
 void BrowserProcessImpl::PreMainMessageLoopRun() {
   TRACE_EVENT0("startup", "BrowserProcessImpl::PreMainMessageLoopRun");
   SCOPED_UMA_HISTOGRAM_TIMER(
       "Startup.BrowserProcessImpl_PreMainMessageLoopRunTime");
 
+  // At this stage of startup, metrics should be good to go and we can
+  // initialize the metrics data use forwarder on the IO thread state object.
+  io_thread()->InitMetricsDataUseForwarder();
+
   // browser_policy_connector() is created very early because local_state()
   // needs policy to be initialized with the managed preference values.
   // However, policy fetches from the network and loading of disk caches
   // requires that threads are running; this Init() call lets the connector
   // resume its initialization now that the loops are spinning and the
   // system request context is available for the fetchers.
   browser_policy_connector()->Init(local_state(), system_request_context());
 
   if (local_state_->IsManagedPreference(prefs::kDefaultBrowserSettingEnabled))
     ApplyDefaultBrowserPolicy();
@@ skipping 320 matching lines @@
 }
 
 void BrowserProcessImpl::OnAutoupdateTimer() {
   if (CanAutorestartForUpdate()) {
     DLOG(WARNING) << "Detected update.  Restarting browser.";
     RestartBackgroundInstance();
   }
 }
 
 #endif  // (defined(OS_WIN) || defined(OS_LINUX)) && !defined(OS_CHROMEOS)