Refactor HashedExtensionMetrics into ExtensionsMetricsProvider.

chrome/browser/metrics/metrics_services_manager.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 "chrome/browser/metrics/metrics_services_manager.h"
 
+#include "chrome/browser/metrics/extensions_metrics_provider.h"
 #include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/metrics/metrics_state_manager.h"
 #include "chrome/browser/metrics/variations/variations_service.h"
 #include "components/rappor/rappor_service.h"
 
 MetricsServicesManager::MetricsServicesManager(PrefService* local_state)
     : local_state_(local_state) {
   DCHECK(local_state);
 }
 
 MetricsServicesManager::~MetricsServicesManager() {
 }
 
 MetricsService* MetricsServicesManager::GetMetricsService() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  if (!metrics_service_)
+  if (!metrics_service_) {
     metrics_service_.reset(new MetricsService(GetMetricsStateManager()));
+    metrics_service_->RegisterMetricsProvider(
+        scoped_ptr<metrics::MetricsProvider>(
+            new ExtensionsMetricsProvider(GetMetricsStateManager())));
+  }
   return metrics_service_.get();
 }
 
 rappor::RapporService* MetricsServicesManager::GetRapporService() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!rappor_service_)
     rappor_service_.reset(new rappor::RapporService);
   return rappor_service_.get();
 }
 
 chrome_variations::VariationsService*
 MetricsServicesManager::GetVariationsService() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!variations_service_) {
     variations_service_ =
         chrome_variations::VariationsService::Create(local_state_,
                                                      GetMetricsStateManager());
   }
   return variations_service_.get();
 }
 
 metrics::MetricsStateManager* MetricsServicesManager::GetMetricsStateManager() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!metrics_state_manager_)
     metrics_state_manager_ = metrics::MetricsStateManager::Create(local_state_);
   return metrics_state_manager_.get();
 }