Revert of Reduce plugin_metrics_provider_ usage in MetricsService

chrome/browser/metrics/metrics_service.cc

 // Copyright (c) 2012 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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It is
@@ skipping 1295 matching lines @@
   // (and that we don't use some alternate path, and not call LogCleanShutdown).
   clean_shutdown_status_ = CLEANLY_SHUTDOWN;
 
   RecordBooleanPrefValue(prefs::kStabilityExitedCleanly, true);
   local_state_->SetInteger(prefs::kStabilityExecutionPhase,
                            MetricsService::SHUTDOWN_COMPLETE);
 }
 
 void MetricsService::LogPluginLoadingError(const base::FilePath& plugin_path) {
 #if defined(ENABLE_PLUGINS)
+  // TODO(asvitkine): Move this out of here.
   plugin_metrics_provider_->LogPluginLoadingError(plugin_path);
 #endif
 }
 
 bool MetricsService::ShouldLogEvents() {
   // We simply don't log events to UMA if there is a single incognito
   // session visible. The problem is that we always notify using the orginal
   // profile in order to simplify notification processing.
   return !client_->IsOffTheRecordSessionActive();
 }
 
 void MetricsService::RecordBooleanPrefValue(const char* path, bool value) {
   DCHECK(IsSingleThreaded());
   local_state_->SetBoolean(path, value);
   RecordCurrentState(local_state_);
 }
 
 void MetricsService::RecordCurrentState(PrefService* pref) {
   pref->SetInt64(prefs::kStabilityLastTimestampSec, Time::Now().ToTimeT());
 
-  for (size_t i = 0; i < metrics_providers_.size(); ++i)
-    metrics_providers_[i]->RecordCurrentState();
+#if defined(ENABLE_PLUGINS)
+  plugin_metrics_provider_->RecordPluginChanges();
+#endif
 }