Reduce plugin_metrics_provider_ usage in MetricsService

chrome/browser/metrics/metrics_services_manager.h

Index: chrome/browser/metrics/metrics_services_manager.h
diff --git a/chrome/browser/metrics/metrics_services_manager.h b/chrome/browser/metrics/metrics_services_manager.h
index 6e16b162bca16cb5cddce4580eb04d973c7892cc..1d7717722a8a5488b91024b5d229762302ffcfdf 100644
--- a/chrome/browser/metrics/metrics_services_manager.h
+++ b/chrome/browser/metrics/metrics_services_manager.h
@@ -13,6 +13,10 @@ class ChromeMetricsServiceClient;
 class MetricsService;
 class PrefService;
 
+namespace base {
+class FilePath;
+}
+
 namespace metrics {
 class MetricsStateManager;
 }
@@ -43,6 +47,9 @@ class MetricsServicesManager {
   // Returns the VariationsService, creating it if it hasn't been created yet.
   chrome_variations::VariationsService* GetVariationsService();
 
+  // Should be called when a plugin loading error occurs.
+  void OnPluginLoadingError(const base::FilePath& plugin_path);
+
  private:
   metrics::MetricsStateManager* GetMetricsStateManager();