histogram synchronizer code between renderer and browser for UMA and about_histogram

chrome/browser/browser_main.cc

Index: chrome/browser/browser_main.cc
===================================================================
--- chrome/browser/browser_main.cc	(revision 15278)
+++ chrome/browser/browser_main.cc	(working copy)
@@ -40,6 +40,7 @@
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/histogram_synchronizer.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/l10n_util.h"
 #include "chrome/common/main_function_params.h"
@@ -340,6 +341,13 @@
   // Initialize histogram statistics gathering system.
   StatisticsRecorder statistics;
 
+  // Initialize histogram synchronizer system. This is a singleton and is used
+  // for posting tasks via NewRunnableMethod. Its deleted when it goes out of
+  // scope. Even though NewRunnableMethod does AddRef and Release, the object
+  // will not be deleted after the Task is executed.
+  scoped_refptr<HistogramSynchronizer> histogram_synchronizer =
+      new HistogramSynchronizer();
+
   // Initialize the shared instance of user data manager.
   scoped_ptr<UserDataManager> user_data_manager(UserDataManager::Create());