Refactor HashedExtensionMetrics into ExtensionsMetricsProvider.

chrome/browser/metrics/metrics_services_manager.cc

Index: chrome/browser/metrics/metrics_services_manager.cc
diff --git a/chrome/browser/metrics/metrics_services_manager.cc b/chrome/browser/metrics/metrics_services_manager.cc
index 002f18383235aebe6ef0c5202704345f570b54c1..63559c2cc57c096c9ef3b0feae8c35a8fb808336 100644
--- a/chrome/browser/metrics/metrics_services_manager.cc
+++ b/chrome/browser/metrics/metrics_services_manager.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -19,8 +20,12 @@ 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();
 }