Move the thread hop for UMA user actions from content:: to base::.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 273252ef2c04c1687e91268b74fd5fc49df6fd9d..12dba502baccb722710581981650f72d2a19f4e6 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -22,6 +22,7 @@
 #include "base/files/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/metrics/user_metrics.h"
 #include "base/path_service.h"
 #include "base/profiler/scoped_profile.h"
 #include "base/profiler/scoped_tracker.h"
@@ -666,6 +667,10 @@ void ChromeBrowserMainParts::SetupMetricsAndFieldTrials() {
   // but before field trials are set up (so that client ID is available for
   // one-time randomized field trials).
 
+  // Set the thread on which to execute RecordAction.
+  base::SetRecordActionTaskRunner(
+      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI));
+
   // Initialize FieldTrialList to support FieldTrials that use one-time
   // randomization.
   metrics::MetricsService* metrics = browser_process_->metrics_service();