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..d37d4f3f150806e1a3c1cee27fbc6c0baf667b10 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 +346,12 @@ 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),
+                            static_cast<int>(SyncResult::COUNT));

[Ilya Sherman, 2015/05/15 20:41:31]

nit: No need for the static_casts.

[dzhioev (left Google), 2015/05/15 21:14:42]

static_cast is needed here, because the enum is a C++11 strongly typed enum
(enum class).

[Ilya Sherman, 2015/05/15 21:34:54]

Ah, bummer.  I'm generally a fan of strongly typed enums, but it's too bad that
they don't play very nicely with the UMA_HISTOGRAM_ENUMERATION macro.  I guess
we'd need templates to fix that?

+}
+
 }  // namespace chromeos