Revert of Eliminate //chrome dependencies from MetricsServicesManager

ios/chrome/browser/metrics/ios_chrome_metrics_service_client.cc

 // Copyright 2015 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 "ios/chrome/browser/metrics/ios_chrome_metrics_service_client.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 87 matching lines @@
   return client.Pass();
 }
 
 // static
 void IOSChromeMetricsServiceClient::RegisterPrefs(
     PrefRegistrySimple* registry) {
   metrics::MetricsService::RegisterPrefs(registry);
   metrics::StabilityMetricsHelper::RegisterPrefs(registry);
 }
 
-metrics::MetricsService* IOSChromeMetricsServiceClient::GetMetricsService() {
-  return metrics_service_.get();
-}
-
 void IOSChromeMetricsServiceClient::SetMetricsClientId(
     const std::string& client_id) {
   crash_keys::SetMetricsClientIdFromGUID(client_id);
 }
 
 void IOSChromeMetricsServiceClient::OnRecordingDisabled() {
   crash_keys::ClearMetricsClientId();
 }
 
 bool IOSChromeMetricsServiceClient::IsOffTheRecordSessionActive() {
@@ skipping 200 matching lines @@
                      base::Unretained(this)));
 }
 
 void IOSChromeMetricsServiceClient::OnTabParented(web::WebState* web_state) {
   metrics_service_->OnApplicationNotIdle();
 }
 
 void IOSChromeMetricsServiceClient::OnURLOpenedFromOmnibox(OmniboxLog* log) {
   metrics_service_->OnApplicationNotIdle();
 }