[UMA, Cleanup] Remove an unneeded timing-related histogram.

chromecast/browser/metrics/external_metrics.cc

Index: chromecast/browser/metrics/external_metrics.cc
diff --git a/chromecast/browser/metrics/external_metrics.cc b/chromecast/browser/metrics/external_metrics.cc
index f26e0ccd9606e5c5d09e28b5ce8bdadfcbfe81ca..679e4be5dba5f0bf487b20625f25ef11bb045936 100644
--- a/chromecast/browser/metrics/external_metrics.cc
+++ b/chromecast/browser/metrics/external_metrics.cc
@@ -12,7 +12,6 @@
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/metrics/statistics_recorder.h"
-#include "base/timer/elapsed_timer.h"
 #include "chromecast/base/metrics/cast_histograms.h"
 #include "chromecast/base/metrics/cast_metrics_helper.h"
 #include "chromecast/browser/metrics/cast_stability_metrics_provider.h"
@@ -131,9 +130,7 @@ int ExternalMetrics::CollectEvents() {
 }
 
 void ExternalMetrics::CollectEventsAndReschedule() {
-  base::ElapsedTimer timer;
   CollectEvents();
-  UMA_HISTOGRAM_TIMES("UMA.CollectExternalEventsTime", timer.Elapsed());
   ScheduleCollector();
 }