Kill NewTabPage.NumberOfMouseOvers.

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

Index: chrome/browser/ui/webui/ntp/ntp_user_data_logger.cc
diff --git a/chrome/browser/ui/webui/ntp/ntp_user_data_logger.cc b/chrome/browser/ui/webui/ntp/ntp_user_data_logger.cc
index 23a7fda4a0aa2711adbe71bd8e1d34e151d53a6b..ab8fcafb4dce8a6b5d6adeb55122e5404ace7ab5 100644
--- a/chrome/browser/ui/webui/ntp/ntp_user_data_logger.cc
+++ b/chrome/browser/ui/webui/ntp/ntp_user_data_logger.cc
@@ -113,9 +113,6 @@ std::string NTPUserDataLogger::GetMostVisitedNavigationHistogramNameForProvider(
 }
 
 void NTPUserDataLogger::EmitNtpStatistics() {
-  UMA_HISTOGRAM_COUNTS("NewTabPage.NumberOfMouseOvers", number_of_mouseovers_);
-  number_of_mouseovers_ = 0;
-
   // We only send statistics once per page.
   // And we don't send if there are no tiles recorded.
   if (has_emitted_ || !number_of_tiles_)
@@ -207,7 +204,6 @@ void NTPUserDataLogger::LogEvent(NTPLoggingEventType event,
       number_of_external_tile_fallbacks_++;
       break;
     case NTP_MOUSEOVER:

[Marc Treib, 2016/06/24 14:48:02]

Remove the case, so it'll fall into the NOTREACHED below.

-      number_of_mouseovers_++;
       break;
     case NTP_TILE_LOADED:
       // The time at which the last tile has loaded (title, thumbnail or single)
@@ -290,7 +286,6 @@ NTPUserDataLogger::NTPUserDataLogger(content::WebContents* contents)
       number_of_thumbnail_errors_(0),
       number_of_gray_tile_fallbacks_(0),
       number_of_external_tile_fallbacks_(0),
-      number_of_mouseovers_(0),
       has_emitted_(false),
       during_startup_(false) {
   during_startup_ = !AfterStartupTaskUtils::IsBrowserStartupComplete();