Eliminate //chrome dependencies from MetricsServicesManager

chrome/browser/metrics/chrome_metrics_service_accessor.h

Index: chrome/browser/metrics/chrome_metrics_service_accessor.h
diff --git a/chrome/browser/metrics/chrome_metrics_service_accessor.h b/chrome/browser/metrics/chrome_metrics_service_accessor.h
index 1bc5b0063bcb6e331185a285b4f94de2ee2e3e76..f5d1f10be36b397e4cc10a61bc9dfd688f28487e 100644
--- a/chrome/browser/metrics/chrome_metrics_service_accessor.h
+++ b/chrome/browser/metrics/chrome_metrics_service_accessor.h
@@ -65,6 +65,7 @@ class ChromeMetricsServiceAccessor : public metrics::MetricsServiceAccessor {
   friend class ::FlashDOMHandler;
   friend class BrowserProcessImpl;
   friend class ChromeExtensionDownloaderFactory;
+  friend class ChromeMetricsServicesManagerClient;
   friend class ChromeRenderMessageFilter;
   friend class DataReductionProxyChromeSettings;
   friend class domain_reliability::DomainReliabilityServiceFactory;
@@ -72,7 +73,6 @@ class ChromeMetricsServiceAccessor : public metrics::MetricsServiceAccessor {
   friend class extensions::FileManagerPrivateIsUMAEnabledFunction;
   friend void InitiateMetricsReportingChange(
       bool, const OnMetricsReportingCallbackType&);
-  friend class MetricsServicesManager;
   friend class options::BrowserOptionsHandler;
   friend bool prerender::IsOmniboxEnabled(Profile* profile);
   friend class safe_browsing::IncidentReportingService;