Add watch time metrics for HTML5 media playback.

media/blink/webmediaplayer_impl.cc

Index: media/blink/webmediaplayer_impl.cc
diff --git a/media/blink/webmediaplayer_impl.cc b/media/blink/webmediaplayer_impl.cc
index 84dd78fc2d15342eabb71b203dfa18494b8d7b74..92d1227db9645b04b44dd78c006f3b503596ccfa 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -37,6 +37,7 @@
 #include "media/base/timestamp_constants.h"
 #include "media/base/video_frame.h"
 #include "media/blink/texttrack_impl.h"
+#include "media/blink/watch_time_reporter.h"
 #include "media/blink/webaudiosourceprovider_impl.h"
 #include "media/blink/webcontentdecryptionmodule_impl.h"
 #include "media/blink/webinbandtexttrack_impl.h"
@@ -129,6 +130,12 @@ gfx::Size GetRotatedVideoSize(VideoRotation rotation, gfx::Size natural_size) {
   return natural_size;
 }
 
+base::TimeDelta GetCurrentTimeInternal(WebMediaPlayerImpl* p_this) {
+  // We wrap currentTime() instead of using pipeline_.GetMediaTime() since there
+  // are a variety of cases in which that time is not accurate.

[sandersd (OOO until July 31), 2016/08/03 22:45:59]

Can you expand on those cases here? (That said, currentTime() is the publicly
exposed information, it's not surprising that it's the correct one to use.)

[DaleCurtis, 2016/08/04 19:14:59]

Done.

+  return base::TimeDelta::FromSecondsD(p_this->currentTime());
+}
+
 }  // namespace
 
 class BufferedDataSourceHostImpl;
@@ -213,7 +220,8 @@ WebMediaPlayerImpl::WebMediaPlayerImpl(
       surface_manager_(params.surface_manager()),
       overlay_surface_id_(SurfaceManager::kNoSurfaceID),
       suppress_destruction_errors_(false),
-      can_suspend_state_(CanSuspendState::UNKNOWN) {
+      can_suspend_state_(CanSuspendState::UNKNOWN),
+      is_encrypted_(false) {
   DCHECK(!adjust_allocated_memory_cb_.is_null());
   DCHECK(renderer_factory_);
   DCHECK(client_);
@@ -394,6 +402,7 @@ void WebMediaPlayerImpl::play() {
   if (data_source_)
     data_source_->MediaIsPlaying();
 
+  watch_time_reporter_->OnPlaying();
   media_log_->AddEvent(media_log_->CreateEvent(MediaLogEvent::PLAY));
   UpdatePlayState();
 }
@@ -423,6 +432,7 @@ void WebMediaPlayerImpl::pause() {
   paused_time_ =
       ended_ ? pipeline_.GetMediaDuration() : pipeline_.GetMediaTime();
 
+  watch_time_reporter_->OnPaused();
   media_log_->AddEvent(media_log_->CreateEvent(MediaLogEvent::PAUSE));
   UpdatePlayState();
 }
@@ -473,6 +483,10 @@ void WebMediaPlayerImpl::DoSeek(base::TimeDelta time, bool time_updated) {
     return;
   }
 
+  // Call this before setting |seeking_| so that the current media time can be
+  // recorded by the reporter.
+  watch_time_reporter_->OnSeeking(time);
+
   // TODO(sandersd): Ideally we would not clear the idle state if
   // |pipeline_controller_| can elide the seek.
   is_idle_ = false;
@@ -519,6 +533,8 @@ void WebMediaPlayerImpl::setVolume(double volume) {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   volume_ = volume;
   pipeline_.SetVolume(volume_ * volume_multiplier_);
+  if (watch_time_reporter_)
+    watch_time_reporter_->OnVolumeChange(volume);
 }
 
 void WebMediaPlayerImpl::setSinkId(
@@ -871,6 +887,7 @@ void WebMediaPlayerImpl::OnEncryptedMediaInitData(
   // TODO(xhwang): Update this UMA name. https://crbug.com/589251
   UMA_HISTOGRAM_COUNTS("Media.EME.NeedKey", 1);
 
+  is_encrypted_ = true;
   encrypted_client_->encrypted(
       ConvertToWebInitDataType(init_data_type), init_data.data(),
       base::saturated_cast<unsigned int>(init_data.size()));
@@ -1023,9 +1040,9 @@ void WebMediaPlayerImpl::OnMetadata(PipelineMetadata metadata) {
 
   pipeline_metadata_ = metadata;
 
+  SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
   UMA_HISTOGRAM_ENUMERATION("Media.VideoRotation", metadata.video_rotation,
                             VIDEO_ROTATION_MAX + 1);
-  SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
 
   if (hasVideo()) {
     pipeline_metadata_.natural_size = GetRotatedVideoSize(
@@ -1042,6 +1059,17 @@ void WebMediaPlayerImpl::OnMetadata(PipelineMetadata metadata) {
     client_->setWebLayer(video_weblayer_.get());
   }
 
+  // Create the watch time reporter and synchronize its initial state.
+  watch_time_reporter_.reset(
+      new WatchTimeReporter(hasAudio(), hasVideo(), !!chunk_demuxer_,
+                            is_encrypted_, pipeline_metadata_.natural_size,
+                            base::Bind(&GetCurrentTimeInternal, this)));

[sandersd (OOO until July 31), 2016/08/03 22:45:59]

What's the reason to not just directly bind currentTime?

[DaleCurtis, 2016/08/04 19:14:59]

The detail of currentTime returning a double is specific to the blink layer and
shouldn't leak into other components (they should use TimeDelta).

+  watch_time_reporter_->OnVolumeChange(volume_);
+  if (delegate_ && delegate_->IsHidden())
+    watch_time_reporter_->OnHidden();
+  else
+    watch_time_reporter_->OnShown();
+
   UpdatePlayState();
 }
 
@@ -1160,6 +1188,9 @@ void WebMediaPlayerImpl::OnVideoOpacityChange(bool opaque) {
 
 void WebMediaPlayerImpl::OnHidden() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
+  if (watch_time_reporter_)
+    watch_time_reporter_->OnHidden();
+
   UpdatePlayState();
 
   // Schedule suspended playing media to be paused if the user doesn't come back
@@ -1169,6 +1200,9 @@ void WebMediaPlayerImpl::OnHidden() {
 
 void WebMediaPlayerImpl::OnShown() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
+  if (watch_time_reporter_)
+    watch_time_reporter_->OnShown();
+
   must_suspend_ = false;
   background_pause_timer_.Stop();
   UpdatePlayState();