Added histograms for tracking new user's priority prefs sync time and results.

chrome/browser/chromeos/login/screens/user_image_screen.h

Index: chrome/browser/chromeos/login/screens/user_image_screen.h
diff --git a/chrome/browser/chromeos/login/screens/user_image_screen.h b/chrome/browser/chromeos/login/screens/user_image_screen.h
index 8afe9c29d584eb6346d8e81ffb1c4dc7e11bea02..ac6e2f9fa827ae5de89af9e4c6cb4720a2302513 100644
--- a/chrome/browser/chromeos/login/screens/user_image_screen.h
+++ b/chrome/browser/chromeos/login/screens/user_image_screen.h
@@ -7,6 +7,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
 #include "chrome/browser/chromeos/camera_presence_notifier.h"
 #include "chrome/browser/chromeos/login/screens/base_screen.h"
 #include "chrome/browser/chromeos/login/screens/user_image_model.h"
@@ -75,6 +76,8 @@ class UserImageScreen : public UserImageModel,
   bool user_selected_image() const { return user_has_selected_image_; }
 
  private:
+  enum class SyncResult { SUCCEED, TIMED_OUT };
+
   // Called when whaiting for sync timed out.
   void OnSyncTimeout();
 
@@ -101,6 +104,9 @@ class UserImageScreen : public UserImageModel,
   // Closes the screen.
   void ExitScreen();
 
+  // Reports sync duration and result to UMA.
+  void ReportSyncResult(SyncResult timed_out) const;
+
   content::NotificationRegistrar notification_registrar_;
 
   scoped_ptr<policy::PolicyChangeRegistrar> policy_registrar_;
@@ -127,6 +133,9 @@ class UserImageScreen : public UserImageModel,
   // True if user has explicitly selected some image.
   bool user_has_selected_image_;
 
+  // The time when we started wait for user image sync.
+  base::Time sync_waiting_start_time_;
+
   DISALLOW_COPY_AND_ASSIGN(UserImageScreen);
 };