Move implementation of BrowserList onto an inner, instantiatable class, BrowserListImpl.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
===================================================================
--- chrome/browser/chrome_browser_main.cc	(revision 146126)
+++ chrome/browser/chrome_browser_main.cc	(working copy)
@@ -86,6 +86,7 @@
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_ui_prefs.h"
 #include "chrome/browser/ui/startup/startup_browser_creator.h"
+#include "chrome/browser/ui/uma_browsing_activity_observer.h"
 #include "chrome/browser/ui/user_data_dir_dialog.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager_backend.h"
 #include "chrome/common/child_process_logging.h"
@@ -1293,6 +1294,7 @@
   // These members must be initialized before returning from this function.
   master_prefs_.reset(new first_run::MasterPrefs);
   browser_creator_.reset(new StartupBrowserCreator);
+  chrome::UMABrowsingActivityObserver::Init();
 
 #if !defined(OS_ANDROID)
   // Convert active labs into switches. This needs to be done before