Desktop NTP: Add a UMA metric NewTabPage.TilesReceivedTime

chrome/browser/ui/webui/ntp/ntp_user_data_logger.h

Index: chrome/browser/ui/webui/ntp/ntp_user_data_logger.h
diff --git a/chrome/browser/ui/webui/ntp/ntp_user_data_logger.h b/chrome/browser/ui/webui/ntp/ntp_user_data_logger.h
index 59e967c25d91cab6b943cac45323427e37fa0e05..f36f2b523dbc0b3dc04372e7a8e619a0828d77ec 100644
--- a/chrome/browser/ui/webui/ntp/ntp_user_data_logger.h
+++ b/chrome/browser/ui/webui/ntp/ntp_user_data_logger.h
@@ -55,6 +55,7 @@ class NTPUserDataLogger
 
   FRIEND_TEST_ALL_PREFIXES(NTPUserDataLoggerTest, TestLogMostVisitedImpression);
   FRIEND_TEST_ALL_PREFIXES(NTPUserDataLoggerTest, TestNumberOfTiles);
+  FRIEND_TEST_ALL_PREFIXES(NTPUserDataLoggerTest, TestLoadTime);
 
   // Number of Most Visited elements on the NTP for logging purposes.
   static const int kNumMostVisited = 8;
@@ -85,6 +86,9 @@ class NTPUserDataLogger
   // corresponding entry in |impression_was_logged_| is true.
   std::vector<ntp_tiles::NTPTileSource> impression_tile_source_;
 
+  // The time we received the NTP_ALL_TILES_RECEIVED event.
+  base::TimeDelta tiles_received_time_;
+
   // Whether we have already emitted NTP stats for this web contents.
   bool has_emitted_;