Started measuring time for session restore process.

This should help us tune absolute timeouts for this process better.

BUG=none
TEST=none

Review URL: https://chromiumcodereview.appspot.com/23444077

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223531 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/login/oauth2_login_manager.cc

@@ -216,6 +216,14 @@ void OAuth2LoginManager::SetSessionRestoreState(
     return;
 
   state_ = state;
+  if (state == OAuth2LoginManager::SESSION_RESTORE_FAILED) {
+    UMA_HISTOGRAM_TIMES("OAuth2Login.SessionRestoreTimeToFailure",
+                        base::Time::Now() - session_restore_start_);
+  } else if (state == OAuth2LoginManager::SESSION_RESTORE_DONE) {
+    UMA_HISTOGRAM_TIMES("OAuth2Login.SessionRestoreTimeToSuccess",
+                        base::Time::Now() - session_restore_start_);
+  }
+
   FOR_EACH_OBSERVER(Observer, observer_list_,
                     OnSessionRestoreStateChanged(user_profile_, state_));
 }