Log operator code histogram on new metric log

chrome/browser/metrics/metrics_service_observer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "cycle_ptrs.h"
+#include "chrome/browser/chrome_browser_metrics_service_observer.h"
 
-namespace WebCore {
-
-void A::trace(Visitor* visitor) {
-    visitor->trace(m_b);
+MetricsServiceObserver::MetricsServiceObserver() {
 }
 
-void B::trace(Visitor* visitor) {
-    visitor->trace(m_a);
+MetricsServiceObserver::~MetricsServiceObserver() {
 }
-
-}