Factor Chrome details out of update manifest fetching.

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 37b02853bc221091c3fff69856456d1adb5749f1..c582c72450cb0320d47b9b886a11de016785da06 100644
--- a/chrome/browser/metrics/chrome_metrics_service_accessor.h
+++ b/chrome/browser/metrics/chrome_metrics_service_accessor.h
@@ -13,6 +13,7 @@
 #include "chrome/browser/metrics/metrics_service_accessor.h"
 
 class ChromeBrowserMetricsServiceObserver;
+class ExtensionService;
 class Profile;
 
 namespace {
@@ -44,8 +45,7 @@ class ChromeMetricsServiceAccessor : public MetricsServiceAccessor {
   friend class ChromeRenderMessageFilter;
   friend class ::CrashesDOMHandler;
   friend class DataReductionProxyChromeSettings;
-  friend class extensions::ExtensionDownloader;
-  friend class extensions::ManifestFetchData;
+  friend class ExtensionService;
   friend class extensions::MetricsPrivateGetIsCrashReportingEnabledFunction;
   friend class ::FlashDOMHandler;
   friend class system_logs::ChromeInternalLogSource;