Log operator code histogram on new metric log

chrome/browser/chrome_browser_main.h

Index: chrome/browser/chrome_browser_main.h
diff --git a/chrome/browser/chrome_browser_main.h b/chrome/browser/chrome_browser_main.h
index 0d1b51c1a83507d19c4d9cfebe036698ed67dc06..7fc3160a5475e9e9a7789302501109bc0aac020b 100644
--- a/chrome/browser/chrome_browser_main.h
+++ b/chrome/browser/chrome_browser_main.h
@@ -20,6 +20,7 @@
 
 class BrowserProcessImpl;
 class ChromeBrowserMainExtraParts;
+class ChromeBrowserMetricsLogObserver;
 class FieldTrialSynchronizer;
 class MetricsService;
 class PrefService;
@@ -151,6 +152,9 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
   // SetupMetricsAndFieldTrials is called.
   scoped_ptr<base::FieldTrialList> field_trial_list_;
 
+  // Observe and log histograms on new metric logs.
+  scoped_ptr<ChromeBrowserMetricsLogObserver> browser_metrics_log_observer_;
+
   ChromeBrowserFieldTrials browser_field_trials_;
 
   // Vector of additional ChromeBrowserMainExtraParts.