Added metrics for background video playback.

content/renderer/media/renderer_webmediaplayer_delegate.cc

Index: content/renderer/media/renderer_webmediaplayer_delegate.cc
diff --git a/content/renderer/media/renderer_webmediaplayer_delegate.cc b/content/renderer/media/renderer_webmediaplayer_delegate.cc
index 24dc39d79529c7e630986317a29d188373d725f7..aab04e626e21d9d38efbdc34d4229a7d601f21e3 100644
--- a/content/renderer/media/renderer_webmediaplayer_delegate.cc
+++ b/content/renderer/media/renderer_webmediaplayer_delegate.cc
@@ -7,10 +7,21 @@
 #include <stdint.h>
 
 #include "base/auto_reset.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/metrics/user_metrics_action.h"
 #include "content/common/media/media_player_delegate_messages.h"
 #include "content/public/renderer/render_frame.h"
+#include "content/public/renderer/render_thread.h"
 #include "third_party/WebKit/public/platform/WebMediaPlayer.h"
 
+namespace {
+
+void RecordAction(const base::UserMetricsAction& action) {
+  content::RenderThread::Get()->RecordAction(action);
+}
+
+}  // namespace
+
 namespace media {
 
 RendererWebMediaPlayerDelegate::RendererWebMediaPlayerDelegate(
@@ -80,12 +91,16 @@ bool RendererWebMediaPlayerDelegate::IsPlayingBackgroundVideo() {
 void RendererWebMediaPlayerDelegate::WasHidden() {
   for (IDMap<Observer>::iterator it(&id_map_); !it.IsAtEnd(); it.Advance())
     it.GetCurrentValue()->OnHidden();
+
+  RecordAction(base::UserMetricsAction("Media.Hidden"));
 }
 
 void RendererWebMediaPlayerDelegate::WasShown() {
-  is_playing_background_video_ = false;
+  SetIsPlayingBackgroundVideo(false);
   for (IDMap<Observer>::iterator it(&id_map_); !it.IsAtEnd(); it.Advance())
     it.GetCurrentValue()->OnShown();
+
+  RecordAction(base::UserMetricsAction("Media.Shown"));
 }
 
 bool RendererWebMediaPlayerDelegate::OnMessageReceived(
@@ -115,18 +130,22 @@ void RendererWebMediaPlayerDelegate::OnMediaDelegatePause(int delegate_id) {
   Observer* observer = id_map_.Lookup(delegate_id);
   if (observer) {
     if (playing_videos_.find(delegate_id) != playing_videos_.end())
-      is_playing_background_video_ = false;
+      SetIsPlayingBackgroundVideo(false);
     observer->OnPause();
   }
+
+  RecordAction(base::UserMetricsAction("Media.RemoteControls.Pause"));
 }
 
 void RendererWebMediaPlayerDelegate::OnMediaDelegatePlay(int delegate_id) {
   Observer* observer = id_map_.Lookup(delegate_id);
   if (observer) {
     if (playing_videos_.find(delegate_id) != playing_videos_.end())
-      is_playing_background_video_ = IsHidden();
+      SetIsPlayingBackgroundVideo(IsHidden());
     observer->OnPlay();
   }
+
+  RecordAction(base::UserMetricsAction("Media.RemoteControls.Play"));
 }
 
 void RendererWebMediaPlayerDelegate::OnMediaDelegateSuspendAllMediaPlayers() {
@@ -193,6 +212,22 @@ void RendererWebMediaPlayerDelegate::CleanupIdleDelegates() {
     idle_cleanup_timer_.Stop();
 }
 
+void RendererWebMediaPlayerDelegate::SetIsPlayingBackgroundVideo(
+    bool is_playing) {
+  if (is_playing_background_video_ == is_playing) return;
+
+  if (is_playing_background_video_) {
+    UMA_HISTOGRAM_LONG_TIMES(
+        "Media.Session.BackgroundTime",
+        base::TimeTicks::Now() - background_video_playing_start_time_);

[DaleCurtis, 2016/08/05 17:39:22]

Keep in mind that once you start talking about elapsed real time you are
including things like system suspend, etc. So some massive numbers can show up
in your data set unexpectedly. If you don't want this the typical thing to do is
use a PowerObserver to cancel during suspend.

[whywhat, 2016/08/05 20:49:24]

Good point. I assume nothing can happen between OnSuspend and OnResume? I've
added some logic to subtract time spend in power suspended mode from the
measurements.

+    RecordAction(base::UserMetricsAction("Media.Session.BackgroundSuspend"));
+  } else {
+    background_video_playing_start_time_ = base::TimeTicks::Now();
+    RecordAction(base::UserMetricsAction("Media.Session.BackgroundResume"));
+  }
+  is_playing_background_video_ = is_playing;
+}
+
 void RendererWebMediaPlayerDelegate::OnDestruct() {
   delete this;
 }