Reduce plugin_metrics_provider_ usage in MetricsService

chrome/test/base/testing_browser_process.h

Index: chrome/test/base/testing_browser_process.h
diff --git a/chrome/test/base/testing_browser_process.h b/chrome/test/base/testing_browser_process.h
index 3ecdf479a1b54e2e963391335aa05c3e6d1e64f1..fdc0f60b8046e67ffefc1888ee87b7104ff06353 100644
--- a/chrome/test/base/testing_browser_process.h
+++ b/chrome/test/base/testing_browser_process.h
@@ -57,6 +57,7 @@ class TestingBrowserProcess : public BrowserProcess {
   virtual void ResourceDispatcherHostCreated() OVERRIDE;
   virtual void EndSession() OVERRIDE;
   virtual MetricsService* metrics_service() OVERRIDE;
+  virtual PluginMetricsProvider* plugin_metrics_provider() OVERRIDE;
   virtual rappor::RapporService* rappor_service() OVERRIDE;
   virtual IOThread* io_thread() OVERRIDE;
   virtual WatchDogThread* watchdog_thread() OVERRIDE;