Don't cache the IO thread in the MetricsService

chrome/browser/metrics/metrics_service.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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It
@@ skipping 140 matching lines @@
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/process_map.h"
+#include "chrome/browser/io_thread.h"
 #include "chrome/browser/memory_details.h"
 #include "chrome/browser/metrics/histogram_synchronizer.h"
 #include "chrome/browser/metrics/metrics_log.h"
 #include "chrome/browser/metrics/metrics_log_serializer.h"
 #include "chrome/browser/metrics/metrics_reporting_scheduler.h"
 #include "chrome/browser/net/http_pipelining_compatibility_client.h"
 #include "chrome/browser/net/network_stats.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 214 matching lines @@
   local_state->ClearPref(prefs::kMetricsInitialLogsXml);
   local_state->ClearPref(prefs::kMetricsOngoingLogsXml);
   local_state->ClearPref(prefs::kMetricsInitialLogsProto);
   local_state->ClearPref(prefs::kMetricsOngoingLogsProto);
 }
 
 MetricsService::MetricsService()
     : recording_active_(false),
       reporting_active_(false),
       state_(INITIALIZED),
-      io_thread_(NULL),
       idle_since_last_transmission_(false),
       next_window_id_(0),
       ALLOW_THIS_IN_INITIALIZER_LIST(self_ptr_factory_(this)),
       ALLOW_THIS_IN_INITIALIZER_LIST(state_saver_factory_(this)),
       waiting_for_asynchronus_reporting_step_(false) {
   DCHECK(IsSingleThreaded());
   InitializeMetricsState();
 
   base::Closure callback = base::Bind(&MetricsService::StartScheduledUpload,
                                       self_ptr_factory_.GetWeakPtr());
@@ skipping 374 matching lines @@
   PluginService::GetInstance()->GetPlugins(
       base::Bind(&MetricsService::OnInitTaskGotPluginInfo,
           self_ptr_factory_.GetWeakPtr()));
 }
 
 void MetricsService::OnInitTaskGotPluginInfo(
     const std::vector<webkit::WebPluginInfo>& plugins) {
   DCHECK_EQ(state_, INIT_TASK_SCHEDULED);
   plugins_ = plugins;
 
-  io_thread_ = g_browser_process->io_thread();
   if (state_ == INIT_TASK_SCHEDULED)
     state_ = INIT_TASK_DONE;
 }
 
 std::string MetricsService::GenerateClientID() {
   return guid::GenerateGUID();
 }
 
 //------------------------------------------------------------------------------
 // State save methods
@@ skipping 460 matching lines @@
   }
 
   // Error 400 indicates a problem with the log, not with the server, so
   // don't consider that a sign that the server is in trouble.
   bool server_is_healthy = upload_succeeded || response_code_ == 400;
 
   scheduler_->UploadFinished(server_is_healthy,
                              log_manager_.has_unsent_logs());
 
   // Collect network stats if UMA upload succeeded.
-  if (server_is_healthy && io_thread_) {
-    chrome_browser_net::CollectNetworkStats(network_stats_server_, io_thread_);
+  IOThread* io_thread = g_browser_process->io_thread();
+  if (server_is_healthy && io_thread) {
+    chrome_browser_net::CollectNetworkStats(network_stats_server_, io_thread);
     chrome_browser_net::CollectPipeliningCapabilityStatsOnUIThread(
-        http_pipelining_test_server_, io_thread_);
+        http_pipelining_test_server_, io_thread);
   }
 
   // Reset the cached response data.
   response_code_ = kNoResponseCode;
   response_data_ = std::string();
   response_status_ = std::string();
 }
 
 void MetricsService::LogBadResponseCode() {
   VLOG(1) << "Verify your metrics logs are formatted correctly.  Verify server "
@@ skipping 385 matching lines @@
   if (local_state) {
     const PrefService::Preference* uma_pref =
         local_state->FindPreference(prefs::kMetricsReportingEnabled);
     if (uma_pref) {
       bool success = uma_pref->GetValue()->GetAsBoolean(&result);
       DCHECK(success);
     }
   }
   return result;
 }