Autoplay time metric

third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp

Index: third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp
diff --git a/third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp b/third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp
index 410dcc50e41ceff3d8ab904d199a1d7c02fe58e0..09d38142f9466741908e09b95778c2acd508dffd 100644
--- a/third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp
+++ b/third_party/WebKit/Source/core/html/media/AutoplayUmaHelper.cpp
@@ -21,6 +21,8 @@ namespace {
 
 const int32_t kMaxOffscreenDurationUmaMS = 60 * 60 * 1000;
 const int32_t kOffscreenDurationUmaBucketCount = 50;
+const int32_t kMaxWaitTimeUmaMS = 30 * 1000;
+const int32_t kWaitTimeBucketCount = 50;
 
 }  // namespace
 
@@ -36,7 +38,8 @@ AutoplayUmaHelper::AutoplayUmaHelper(HTMLMediaElement* element)
       muted_video_autoplay_offscreen_start_time_ms_(0),
       muted_video_autoplay_offscreen_duration_ms_(0),
       is_visible_(false),
-      muted_video_offscreen_duration_visibility_observer_(nullptr) {}
+      muted_video_offscreen_duration_visibility_observer_(nullptr),
+      load_start_time_ms_(0.0) {}
 
 AutoplayUmaHelper::~AutoplayUmaHelper() = default;
 
@@ -44,7 +47,19 @@ bool AutoplayUmaHelper::operator==(const EventListener& other) const {
   return this == &other;
 }
 
+void AutoplayUmaHelper::OnLoadStarted(WebMediaPlayer::LoadType load_type) {
+  if (load_type == WebMediaPlayer::kLoadTypeURL) {
+    load_start_time_ms_ = MonotonicallyIncreasingTimeMS();
+  }

[mlamouri (slow - plz ping), 2017/05/15 14:31:21]

style: should drop the { }

[hubbe, 2017/05/15 22:32:00]

Done.

+}
+
 void AutoplayUmaHelper::OnAutoplayInitiated(AutoplaySource source) {
+  int32_t autoplay_wait_time_ms = -1;

[mlamouri (slow - plz ping), 2017/05/15 14:31:20]

You could use optional here instead of setting to -1 and having to handle 64
bits and 32 bits int in the condition body below. I think it would be more
readable but I have no strong opinion.

[hubbe, 2017/05/15 22:32:00]

Acknowledged.

+  if (load_start_time_ms_ != 0.0) {
+    autoplay_wait_time_ms = static_cast<int32_t>(
+        std::min<int64_t>(MonotonicallyIncreasingTimeMS() - load_start_time_ms_,
+                          std::numeric_limits<int32_t>::max()));
+  }
   DEFINE_STATIC_LOCAL(EnumerationHistogram, video_histogram,
                       ("Media.Video.Autoplay",
                        static_cast<int>(AutoplaySource::kNumberOfUmaSources)));
@@ -58,6 +73,19 @@ void AutoplayUmaHelper::OnAutoplayInitiated(AutoplaySource source) {
       EnumerationHistogram, blocked_muted_video_histogram,
       ("Media.Video.Autoplay.Muted.Blocked", kAutoplayBlockedReasonMax));
 
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, wait_time_video_attrib_histogram,
+                      ("Media.Video.Autoplay.Video.Attribute.WaitTime", 1,
+                       kMaxWaitTimeUmaMS, kWaitTimeBucketCount));
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, wait_time_audio_attrib_histogram,
+                      ("Media.Video.Autoplay.Audio.Attribute.WaitTime", 1,
+                       kMaxWaitTimeUmaMS, kWaitTimeBucketCount));
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, wait_time_video_play_histogram,
+                      ("Media.Video.Autoplay.Video.PlayMethod.WaitTime", 1,
+                       kMaxWaitTimeUmaMS, kWaitTimeBucketCount));
+  DEFINE_STATIC_LOCAL(CustomCountHistogram, wait_time_audio_play_histogram,
+                      ("Media.Video.Autoplay.Audio.PlayMethod.WaitTime", 1,
+                       kMaxWaitTimeUmaMS, kWaitTimeBucketCount));

[mlamouri (slow - plz ping), 2017/05/15 14:31:21]

Shouldn't this be Media.Audio.Autoplay instead of Media.Video.Autoplay.Audio?

[hubbe, 2017/05/15 22:32:00]

Done.

+
   // Autoplay already initiated
   if (sources_.count(source))
     return;
@@ -69,8 +97,22 @@ void AutoplayUmaHelper::OnAutoplayInitiated(AutoplaySource source) {
     video_histogram.Count(static_cast<int>(source));
     if (element_->muted())
       muted_video_histogram.Count(static_cast<int>(source));
+    if (autoplay_wait_time_ms >= 0) {
+      if (source == AutoplaySource::kAttribute) {
+        wait_time_video_attrib_histogram.Count(autoplay_wait_time_ms);
+      } else if (source == AutoplaySource::kMethod) {
+        wait_time_video_play_histogram.Count(autoplay_wait_time_ms);

[mlamouri (slow - plz ping), 2017/05/15 14:31:20]

Will your change have an effect on `play()`? Autoplaying with `play()` doesn't
follow the same rules as with the attribute. With the attribute you set it and
the UA will decide when to start so it only start on canplaythrough. However,
for `play()`, the usual rules of playback are applied which means that `play()`
will trigger when the ready state is `HAVE_FUTURE_DATA` which is one step before
`HAVE_ENOUGH_DATA`. Will your change affect this? If it does, it will affect all
playback, not only autoplay'd.

[hubbe, 2017/05/15 22:32:00]

It shouldn't affect code that calls play() immediately, as I'm not making any
changes to HAVE_FUTURE_DATA. It should however effect code that waits for the
state to change to canplaythrough.

This is part of the reason I split it out into several metrics. One to see if it
affects the web as a whole (expected answer: no, or within margin of error.) and
one that shows how it affects autoplay (expected answer: yes, but not very
much.)

+      }
+    }
   } else {
     audio_histogram.Count(static_cast<int>(source));
+    if (autoplay_wait_time_ms >= 0) {
+      if (source == AutoplaySource::kAttribute) {
+        wait_time_audio_attrib_histogram.Count(autoplay_wait_time_ms);
+      } else if (source == AutoplaySource::kMethod) {
+        wait_time_audio_play_histogram.Count(autoplay_wait_time_ms);
+      }
+    }
   }
 
   // Record dual source.