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

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

Index: chrome/browser/chromeos/login/screens/user_image_screen.cc
diff --git a/chrome/browser/chromeos/login/screens/user_image_screen.cc b/chrome/browser/chromeos/login/screens/user_image_screen.cc
index f450f9e1afeaec0f1a4d1f195315b08fa22bffdc..e54288129d97e10afbe87aaeb7e00fb9be0e47dc 100644
--- a/chrome/browser/chromeos/login/screens/user_image_screen.cc
+++ b/chrome/browser/chromeos/login/screens/user_image_screen.cc
@@ -125,6 +125,7 @@ void UserImageScreen::OnDecodeImageFailed() {
 
 void UserImageScreen::OnInitialSync(bool local_image_updated) {
   DCHECK(sync_timer_);
+  ReportSyncResult(SyncResult::SUCCEED);
   if (!local_image_updated) {
     sync_timer_.reset();
     GetSyncObserver()->RemoveObserver(this);
@@ -136,6 +137,7 @@ void UserImageScreen::OnInitialSync(bool local_image_updated) {
 }
 
 void UserImageScreen::OnSyncTimeout() {
+  ReportSyncResult(SyncResult::TIMED_OUT);
   sync_timer_.reset();
   GetSyncObserver()->RemoveObserver(this);
   if (is_screen_ready_)
@@ -261,8 +263,10 @@ void UserImageScreen::Show() {
 
   if (GetUser()->CanSyncImage()) {
     if (UserImageSyncObserver* sync_observer = GetSyncObserver()) {
+      sync_waiting_start_time_ = base::Time::Now();
       // We have synced image already.
       if (sync_observer->is_synced()) {
+        ReportSyncResult(SyncResult::SUCCEED);
         ExitScreen();
         return;
       }
@@ -342,4 +346,11 @@ void UserImageScreen::ExitScreen() {
   Finish(BaseScreenDelegate::USER_IMAGE_SELECTED);
 }
 
+void UserImageScreen::ReportSyncResult(SyncResult timed_out) const {
+  base::TimeDelta duration = base::Time::Now() - sync_waiting_start_time_;
+  UMA_HISTOGRAM_TIMES("Login.NewUserPriorityPrefsSyncTime", duration);
+  UMA_HISTOGRAM_ENUMERATION("Login.NewUserPriorityPrefsSyncResult",
+                            static_cast<int>(timed_out), 2);

[Ilya Sherman, 2015/05/15 17:36:40]

nit: Maybe write this as below?  I'm not too happy about the hardcoded 2 -- if
the SyncResult enum were ever expanded, this code path would silently break.

UMA_HISTOGRAM_BOOLEAN("Login.NewUserPriorityPrefsSyncResult",
                      timed_out == SyncResult::TIMED_OUT);

[dzhioev (left Google), 2015/05/15 20:36:50]

I've added |COUNT| element to the enum, and use it here instead of hardcoded
|2|.

+}
+
 }  // namespace chromeos