Remove TimeToDisplayVideo from Cast metrics

As discussed on email:
* This histogram doesn't actually capture the user experience metrics we
  care about
* We are not using this data currently
* CMA backends are inconsistent in whether they call this or not

Since keeping this would add extra work in moving CMA backends into
shared libraries, just remove it.  A feature request ticket has been
filed for writing a better replacement.

BUG=508534

Review URL: https://codereview.chromium.org/1230823002

Cr-Commit-Position: refs/heads/master@{#338085}

3 files changed, 0 insertions, 27 deletions

diff --git a/chromecast/base/metrics/cast_metrics_helper.cc b/chromecast/base/metrics/cast_metrics_helper.cc
index c3e6a8c..6d07b4a 100644
--- a/chromecast/base/metrics/cast_metrics_helper.cc
+++ b/chromecast/base/metrics/cast_metrics_helper.cc
@@ -119,7 +119,6 @@ void CastMetricsHelper::UpdateCurrentAppInfo(const std::string& app_id,
   app_id_ = app_id;
   session_id_ = session_id;
   app_start_time_ = base::TimeTicks::Now();
-  new_startup_time_ = true;
   TagAppStartForGroupedHistograms(app_id_);
   sdk_version_.clear();
 }
@@ -158,19 +157,6 @@ void CastMetricsHelper::LogTimeToFirstPaint() {
   LOG(INFO) << uma_name << " is " << launch_time.InSecondsF() << " seconds.";
 }
 
-void CastMetricsHelper::LogTimeToDisplayVideo() {
-  if (!new_startup_time_) {  // For faster check.
-    return;
-  }
-  MAKE_SURE_THREAD(LogTimeToDisplayVideo);
-  new_startup_time_ = false;
-  base::TimeDelta launch_time = base::TimeTicks::Now() - app_start_time_;
-  const std::string uma_name(GetMetricsNameWithAppName("Startup",
-                                                       "TimeToDisplayVideo"));
-  LogMediumTimeHistogramEvent(uma_name, launch_time);
-  LOG(INFO) << uma_name << " is " << launch_time.InSecondsF() << " seconds.";
-}
-
 void CastMetricsHelper::LogTimeToBufferAv(BufferingType buffering_type,
                                           base::TimeDelta time) {
   MAKE_SURE_THREAD(LogTimeToBufferAv, buffering_type, time);
diff --git a/chromecast/base/metrics/cast_metrics_helper.h b/chromecast/base/metrics/cast_metrics_helper.h
index 0650c0e..6f5c342 100644
--- a/chromecast/base/metrics/cast_metrics_helper.h
+++ b/chromecast/base/metrics/cast_metrics_helper.h
@@ -79,10 +79,6 @@ class CastMetricsHelper {
   // Logs UMA record of the time the app made its first paint.
   virtual void LogTimeToFirstPaint();
 
-  // Logs UMA record of the elapsed time from the app launch
-  // to the time first video frame is displayed.
-  virtual void LogTimeToDisplayVideo();
-
   // Logs UMA record of the time needed to re-buffer A/V.
   virtual void LogTimeToBufferAv(BufferingType buffering_type,
                                  base::TimeDelta time);
@@ -144,11 +140,6 @@ class CastMetricsHelper {
   std::string session_id_;
   std::string sdk_version_;
 
-  // Whether a new app start time has been stored but not recorded.
-  // After the startup time has been used to generate an UMA event,
-  // this is set to false.
-  bool new_startup_time_;
-
   base::TimeTicks previous_video_stat_sample_time_;
 
   MetricsSink* metrics_sink_;
diff --git a/chromecast/base/metrics/cast_metrics_test_helper.cc b/chromecast/base/metrics/cast_metrics_test_helper.cc
index c78abe1..2e4f074 100644
--- a/chromecast/base/metrics/cast_metrics_test_helper.cc
+++ b/chromecast/base/metrics/cast_metrics_test_helper.cc
@@ -23,7 +23,6 @@ class CastMetricsHelperStub : public CastMetricsHelper {
   void UpdateSDKInfo(const std::string& sdk_version) override;
   void LogMediaPlay() override;
   void LogMediaPause() override;
-  void LogTimeToDisplayVideo() override;
   void LogTimeToBufferAv(BufferingType buffering_type,
                          base::TimeDelta time) override;
   void ResetVideoFrameSampling() override;
@@ -65,9 +64,6 @@ void CastMetricsHelperStub::LogMediaPlay() {
 void CastMetricsHelperStub::LogMediaPause() {
 }
 
-void CastMetricsHelperStub::LogTimeToDisplayVideo() {
-}
-
 void CastMetricsHelperStub::LogTimeToBufferAv(BufferingType buffering_type,
                                               base::TimeDelta time) {
 }