Refactor Extension initialization logic. Add tracing and additional histogram.

chrome/browser/extensions/extension_service.h

Index: chrome/browser/extensions/extension_service.h
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index 4b6005d3aec06e20e474de92eaf0ca3f49c4359b..cc5f7aef4354cf1620ffcb397d0205daac287d32 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -500,6 +500,14 @@ class ExtensionService
   // externally managed extension.  If so, uninstall it.
   void CheckExternalUninstall(const std::string& id);
 
+  // Attempt to enable all disabled extensions which the only disabled reason is
+  // reloading.
+  void EnabledReloadableExtensions();
+
+  // Finish install (if possible) of extensions that were still delayed while
+  // the browser was shut down.
+  void MaybeFinishShutdownDelayed();
+
   // Populates greylist_.
   void LoadGreylistFromPrefs();