Don't cache the IO thread in the MetricsService

chrome/browser/metrics/metrics_service.cc

Index: chrome/browser/metrics/metrics_service.cc
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index 9fc36d0e1426054195b69b3d67cbe49cb6b5915e..92ee6021a7e0fea7efb9b6b165200fb54f814285 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -158,6 +158,7 @@
 #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"
@@ -392,7 +393,6 @@ 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)),
@@ -787,7 +787,6 @@ void MetricsService::OnInitTaskGotPluginInfo(
   DCHECK_EQ(state_, INIT_TASK_SCHEDULED);
   plugins_ = plugins;
 
-  io_thread_ = g_browser_process->io_thread();
   if (state_ == INIT_TASK_SCHEDULED)
     state_ = INIT_TASK_DONE;
 }
@@ -1268,10 +1267,11 @@ void MetricsService::OnURLFetchComplete(const content::URLFetcher* source) {
                              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.