[Blink>Media] Moving autoplay logic to AutoplayPolicy

third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
index d3e0fc4ebe09e239b56f59bda8002f00ea4d79a5..3a1b71ec68a2d1a2a740b28fd61e53dd9895b4b5 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
@@ -38,12 +38,10 @@
 #include "core/dom/DOMException.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/ElementTraversal.h"
-#include "core/dom/ElementVisibilityObserver.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/events/Event.h"
-#include "core/frame/ContentSettingsClient.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/LocalFrameClient.h"
@@ -53,6 +51,7 @@
 #include "core/html/HTMLSourceElement.h"
 #include "core/html/HTMLTrackElement.h"
 #include "core/html/TimeRanges.h"
+#include "core/html/media/AutoplayPolicy.h"
 #include "core/html/media/AutoplayUmaHelper.h"
 #include "core/html/media/HTMLMediaElementControlsList.h"
 #include "core/html/media/HTMLMediaSource.h"
@@ -333,41 +332,6 @@ String PreloadTypeToString(WebMediaPlayer::Preload preload_type) {
   return String();
 }
 
-bool IsDocumentCrossOrigin(Document& document) {
-  const LocalFrame* frame = document.GetFrame();
-  return frame && frame->IsCrossOriginSubframe();
-}
-
-bool IsDocumentWhitelisted(Document& document) {
-  DCHECK(document.GetSettings());
-
-  const String& whitelist_scope =
-      document.GetSettings()->GetMediaPlaybackGestureWhitelistScope();
-  if (whitelist_scope.IsNull() || whitelist_scope.IsEmpty())
-    return false;
-
-  return document.Url().GetString().StartsWith(whitelist_scope);
-}
-
-// Return true if and only if the document settings specifies media playback
-// requires user gesture.
-bool ComputeLockedPendingUserGesture(Document& document) {
-  if (!document.GetSettings())
-    return false;
-
-  if (IsDocumentWhitelisted(document)) {
-    return false;
-  }
-
-  if (document.GetSettings()
-          ->GetCrossOriginMediaPlaybackRequiresUserGesture() &&
-      IsDocumentCrossOrigin(document)) {
-    return true;
-  }
-
-  return document.GetSettings()->GetMediaPlaybackRequiresUserGesture();
-}
-
 std::unique_ptr<MediaControls::Factory>& MediaControlsFactory() {
   DEFINE_STATIC_LOCAL(std::unique_ptr<MediaControls::Factory>,
                       media_controls_factory, ());
@@ -505,8 +469,6 @@ HTMLMediaElement::HTMLMediaElement(const QualifiedName& tag_name,
       official_playback_position_needs_update_(true),
       fragment_end_time_(std::numeric_limits<double>::quiet_NaN()),
       pending_action_flags_(0),
-      locked_pending_user_gesture_(false),
-      locked_pending_user_gesture_if_cross_origin_experiment_enabled_(true),
       playing_(false),
       should_delay_load_event_(false),
       have_fired_loaded_data_(false),
@@ -527,17 +489,13 @@ HTMLMediaElement::HTMLMediaElement(const QualifiedName& tag_name,
       video_tracks_(this, VideoTrackList::Create(*this)),
       text_tracks_(this, nullptr),
       audio_source_node_(nullptr),
+      autoplay_policy_(new AutoplayPolicy(this)),
       autoplay_uma_helper_(AutoplayUmaHelper::Create(this)),
       remote_playback_client_(nullptr),
-      autoplay_visibility_observer_(nullptr),
       media_controls_(nullptr),
       controls_list_(HTMLMediaElementControlsList::Create(this)) {
   BLINK_MEDIA_LOG << "HTMLMediaElement(" << (void*)this << ")";
 
-  locked_pending_user_gesture_ = ComputeLockedPendingUserGesture(document);
-  locked_pending_user_gesture_if_cross_origin_experiment_enabled_ =
-      IsDocumentCrossOrigin(document);
-
   LocalFrame* frame = document.GetFrame();
   if (frame) {
     remote_playback_client_ =
@@ -592,14 +550,7 @@ void HTMLMediaElement::DidMoveToNewDocument(Document& old_document) {
       TaskRunnerHelper::Get(TaskType::kUnthrottled, &GetDocument()));
 
   autoplay_uma_helper_->DidMoveToNewDocument(old_document);
-  // If any experiment is enabled, then we want to enable a user gesture by
-  // default, otherwise the experiment does nothing.
-  bool old_document_requires_user_gesture =
-      ComputeLockedPendingUserGesture(old_document);
-  bool new_document_requires_user_gesture =
-      ComputeLockedPendingUserGesture(GetDocument());
-  if (new_document_requires_user_gesture && !old_document_requires_user_gesture)
-    locked_pending_user_gesture_ = true;
+  autoplay_policy_->DidMoveToNewDocument(old_document);
 
   if (should_delay_load_event_) {
     GetDocument().IncrementLoadEventDelayCount();
@@ -612,10 +563,6 @@ void HTMLMediaElement::DidMoveToNewDocument(Document& old_document) {
     old_document.IncrementLoadEventDelayCount();
   }
 
-  if (IsDocumentCrossOrigin(GetDocument()) &&
-      !IsDocumentCrossOrigin(old_document))
-    locked_pending_user_gesture_if_cross_origin_experiment_enabled_ = true;
-
   RemoveElementFromDocumentMap(this, &old_document);
   AddElementToDocumentMap(this, &GetDocument());
 
@@ -845,10 +792,7 @@ String HTMLMediaElement::canPlayType(const String& mime_type) const {
 void HTMLMediaElement::load() {
   BLINK_MEDIA_LOG << "load(" << (void*)this << ")";
 
-  if (IsLockedPendingUserGesture() &&
-      UserGestureIndicator::UtilizeUserGesture()) {
-    UnlockUserGesture();
-  }
+  autoplay_policy_->TryUnlockingUserGesture();
 
   ignore_preload_none_ = true;
   InvokeLoadAlgorithm();
@@ -1481,10 +1425,6 @@ bool HTMLMediaElement::IsMediaDataCORSSameOrigin(SecurityOrigin* origin) const {
           !origin->TaintsCanvas(currentSrc()));
 }
 
-bool HTMLMediaElement::IsInCrossOriginFrame() const {
-  return IsDocumentCrossOrigin(GetDocument());
-}
-
 void HTMLMediaElement::StartProgressEventTimer() {
   if (progress_event_timer_.IsActive())
     return;
@@ -1843,26 +1783,17 @@ void HTMLMediaElement::SetReadyState(ReadyState state) {
     if (ShouldAutoplay()) {
       autoplay_uma_helper_->OnAutoplayInitiated(AutoplaySource::kAttribute);
 
-      if (!IsGestureNeededForPlayback()) {
-        if (IsGestureNeededForPlaybackIfCrossOriginExperimentEnabled()) {
+      if (!autoplay_policy_->IsGestureNeededForPlayback()) {
+        if (autoplay_policy_
+                ->IsGestureNeededForPlaybackIfCrossOriginExperimentEnabled()) {
           autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
               CrossOriginAutoplayResult::kAutoplayBlocked);
         } else {
           autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
               CrossOriginAutoplayResult::kAutoplayAllowed);
         }
-        if (IsHTMLVideoElement() && muted() &&
-            RuntimeEnabledFeatures::autoplayMutedVideosEnabled()) {
-          // We might end up in a situation where the previous
-          // observer didn't had time to fire yet. We can avoid
-          // creating a new one in this case.
-          if (!autoplay_visibility_observer_) {
-            autoplay_visibility_observer_ = new ElementVisibilityObserver(
-                this,
-                WTF::Bind(&HTMLMediaElement::OnVisibilityChangedForAutoplay,
-                          WrapWeakPersistent(this)));
-            autoplay_visibility_observer_->Start();
-          }
+        if (autoplay_policy_->IsEligibleForAutoplayMuted()) {
+          autoplay_policy_->StartAutoplayMutedWhenVisible();
         } else {
           paused_ = false;
           ScheduleEvent(EventTypeNames::play);
@@ -2283,7 +2214,7 @@ String HTMLMediaElement::EffectivePreload() const {
 }
 
 WebMediaPlayer::Preload HTMLMediaElement::EffectivePreloadType() const {
-  if (Autoplay() && !IsGestureNeededForPlayback())
+  if (Autoplay() && !autoplay_policy_->IsGestureNeededForPlayback())
     return WebMediaPlayer::kPreloadAuto;
 
   WebMediaPlayer::Preload preload = PreloadType();
@@ -2329,48 +2260,34 @@ ScriptPromise HTMLMediaElement::playForBindings(ScriptState* script_state) {
 Nullable<ExceptionCode> HTMLMediaElement::Play() {
   BLINK_MEDIA_LOG << "play(" << (void*)this << ")";
 
-  if (!UserGestureIndicator::ProcessingUserGesture()) {
-    autoplay_uma_helper_->OnAutoplayInitiated(AutoplaySource::kMethod);
-    if (IsGestureNeededForPlayback()) {
-      // If we're already playing, then this play would do nothing anyway.
-      // Call playInternal to handle scheduling the promise resolution.
-      if (!paused_) {
-        PlayInternal();
-        return nullptr;
-      }
-
-      autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
-          CrossOriginAutoplayResult::kAutoplayBlocked);
-      String message = ExceptionMessages::FailedToExecute(
-          "play", "HTMLMediaElement",
-          "API can only be initiated by a user gesture.");
-      GetDocument().AddConsoleMessage(ConsoleMessage::Create(
-          kJSMessageSource, kWarningMessageLevel, message));
-      return kNotAllowedError;
-    } else {
-      if (IsGestureNeededForPlaybackIfCrossOriginExperimentEnabled()) {
-        autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
-            CrossOriginAutoplayResult::kAutoplayBlocked);
-      } else {
-        autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
-            CrossOriginAutoplayResult::kAutoplayAllowed);
-      }
-    }
-  } else {
-    autoplay_uma_helper_->RecordCrossOriginAutoplayResult(
-        CrossOriginAutoplayResult::kPlayedWithGesture);
-    UserGestureIndicator::UtilizeUserGesture();
-    UnlockUserGesture();
+  // If we're already playing, then this play would do nothing anyway.
+  // Call playInternal to handle scheduling the promise resolution.
+  if (!paused_) {
+    PlayInternal();
+    return nullptr;
   }

[mlamouri (slow - plz ping), 2017/04/18 13:28:28]

The logic is slightly changing with this change. I'm all for a simpler logic but
what makes you think it will have no side effects?

[Zhiqiang Zhang (Slow), 2017/04/18 16:56:44]

OK, I moved the code a bit so it should have the same behavior now.

 
+  autoplay_policy_->StopAutoplayMutedWhenVisible();
+
   if (error_ && error_->code() == MediaError::kMediaErrSrcNotSupported)
     return kNotSupportedError;
 
-  if (autoplay_visibility_observer_) {
-    autoplay_visibility_observer_->Stop();
-    autoplay_visibility_observer_ = nullptr;
+  // The only place to call IsAutoplayAllowedFromPlayMethod(), don't call from
+  // anywhere else!

[mlamouri (slow - plz ping), 2017/04/18 13:28:28]

Comment is out of date, right?

[Zhiqiang Zhang (Slow), 2017/04/18 16:56:44]

Done.

+  Nullable<ExceptionCode> exception_code =
+      autoplay_policy_->CheckPlayMethodAllowed();
+
+  if (exception_code == kNotAllowedError) {
+    String message = ExceptionMessages::FailedToExecute(
+        "play", "HTMLMediaElement",
+        "API can only be initiated by a user gesture.");
+    GetDocument().AddConsoleMessage(ConsoleMessage::Create(
+        kJSMessageSource, kWarningMessageLevel, message));
+    return exception_code;
   }
 
+  DCHECK(exception_code.IsNull());
+
   PlayInternal();
 
   return nullptr;
@@ -2410,11 +2327,7 @@ void HTMLMediaElement::PlayInternal() {
 void HTMLMediaElement::pause() {
   BLINK_MEDIA_LOG << "pause(" << (void*)this << ")";
 
-  if (autoplay_visibility_observer_) {
-    autoplay_visibility_observer_->Stop();
-    autoplay_visibility_observer_ = nullptr;
-  }
-
+  autoplay_policy_->StopAutoplayMutedWhenVisible();
   PauseInternal();
 }
 
@@ -2562,41 +2475,26 @@ void HTMLMediaElement::setMuted(bool muted) {
   if (muted_ == muted)
     return;
 
-  bool was_autoplaying_muted = IsAutoplayingMuted();
-  bool was_pending_autoplay_muted = autoplay_visibility_observer_ && paused() &&
-                                    muted_ && IsLockedPendingUserGesture();
-
+  // TODO(zqzhang): use TryUnlockingUserGesture?
   if (UserGestureIndicator::ProcessingUserGesture())
-    UnlockUserGesture();
+    autoplay_policy_->UnlockUserGesture();
+
+  bool should_pause_after_unmute =
+      autoplay_policy_->CheckUnmuteShouldPauseAutoplay();

[mlamouri (slow - plz ping), 2017/04/18 13:28:28]

Not sure this is at the right place. Should this be called before
UnlockUserGesture?

[Zhiqiang Zhang (Slow), 2017/04/18 16:56:44]

The logic won't change actually.
The original logic was to check whether the video was autoplaying muted. If yes,
and and there's no user gesture, we should pause the video.
The gesture is unlocked before the gesture check.

The CheckUnmuteShouldPauseAutoplay (now called RequestAutoplayUnmute) does just
that :)

 
   muted_ = muted;
 
   ScheduleEvent(EventTypeNames::volumechange);
 
-  // If an element autoplayed while muted, it needs to be unlocked to unmute,
-  // otherwise, it will be paused.
-  if (was_autoplaying_muted) {
-    if (IsGestureNeededForPlayback()) {
-      pause();
-      autoplay_uma_helper_->RecordAutoplayUnmuteStatus(
-          AutoplayUnmuteActionStatus::kFailure);
-    } else {
-      autoplay_uma_helper_->RecordAutoplayUnmuteStatus(
-          AutoplayUnmuteActionStatus::kSuccess);
-    }
-  }
+  if (should_pause_after_unmute)
+    pause();
 
   // This is called after the volumechange event to make sure isAutoplayingMuted
   // returns the right value when webMediaPlayer receives the volume update.
   if (GetWebMediaPlayer())
     GetWebMediaPlayer()->SetVolume(EffectiveMediaVolume());
 
-  // If an element was a candidate for autoplay muted but not visible, it will
-  // have a visibility observer ready to start its playback.
-  if (was_pending_autoplay_muted) {
-    autoplay_visibility_observer_->Stop();
-    autoplay_visibility_observer_ = nullptr;
-  }
+  autoplay_policy_->StopAutoplayMutedWhenVisible();
 }
 
 double HTMLMediaElement::EffectiveMediaVolume() const {
@@ -3318,15 +3216,6 @@ WebMediaPlayer::TrackId HTMLMediaElement::GetSelectedVideoTrackId() {
   return track->id();
 }
 
-bool HTMLMediaElement::IsAutoplayingMuted() {
-  if (!IsHTMLVideoElement() ||
-      !RuntimeEnabledFeatures::autoplayMutedVideosEnabled()) {
-    return false;
-  }
-
-  return !paused() && muted() && IsLockedPendingUserGesture();
-}
-
 void HTMLMediaElement::RequestReload(const WebURL& new_url) {
   DCHECK(GetWebMediaPlayer());
   DCHECK(!src_object_);
@@ -3336,6 +3225,10 @@ void HTMLMediaElement::RequestReload(const WebURL& new_url) {
   StartPlayerLoad(new_url);
 }
 
+bool HTMLMediaElement::IsAutoplayingMuted() {
+  return autoplay_policy_->IsAutoplayingMuted();
+}
+
 // MediaPlayerPresentation methods
 void HTMLMediaElement::Repaint() {
   if (web_layer_)
@@ -3933,7 +3826,7 @@ DEFINE_TRACE(HTMLMediaElement) {
   visitor->Trace(audio_source_provider_);
   visitor->Trace(autoplay_uma_helper_);
   visitor->Trace(src_object_);
-  visitor->Trace(autoplay_visibility_observer_);
+  visitor->Trace(autoplay_policy_);
   visitor->Trace(media_controls_);
   visitor->Trace(controls_list_);
   visitor->template RegisterWeakMembers<HTMLMediaElement,
@@ -3983,60 +3876,6 @@ void HTMLMediaElement::SelectInitialTracksIfNecessary() {
     videoTracks().AnonymousIndexedGetter(0)->setSelected(true);
 }
 
-bool HTMLMediaElement::IsLockedPendingUserGesture() const {
-  return locked_pending_user_gesture_;
-}
-
-void HTMLMediaElement::UnlockUserGesture() {
-  locked_pending_user_gesture_ = false;
-  locked_pending_user_gesture_if_cross_origin_experiment_enabled_ = false;
-}
-
-bool HTMLMediaElement::IsGestureNeededForPlayback() const {
-  if (!locked_pending_user_gesture_)
-    return false;
-
-  return IsGestureNeededForPlaybackIfPendingUserGestureIsLocked();
-}
-
-bool HTMLMediaElement::
-    IsGestureNeededForPlaybackIfCrossOriginExperimentEnabled() const {
-  if (!locked_pending_user_gesture_if_cross_origin_experiment_enabled_)
-    return false;
-
-  return IsGestureNeededForPlaybackIfPendingUserGestureIsLocked();
-}
-
-bool HTMLMediaElement::IsGestureNeededForPlaybackIfPendingUserGestureIsLocked()
-    const {
-  if (GetLoadType() == WebMediaPlayer::kLoadTypeMediaStream)
-    return false;
-
-  // We want to allow muted video to autoplay if:
-  // - the flag is enabled;
-  // - Data Saver is not enabled;
-  // - Preload was not disabled (low end devices);
-  // - Autoplay is enabled in settings;
-  if (IsHTMLVideoElement() && muted() &&
-      RuntimeEnabledFeatures::autoplayMutedVideosEnabled() &&
-      !(GetDocument().GetSettings() &&
-        GetDocument().GetSettings()->GetDataSaverEnabled()) &&
-      !(GetDocument().GetSettings() &&
-        GetDocument().GetSettings()->GetForcePreloadNoneForMediaElements()) &&
-      IsAutoplayAllowedPerSettings()) {
-    return false;
-  }
-
-  return true;
-}
-
-bool HTMLMediaElement::IsAutoplayAllowedPerSettings() const {
-  LocalFrame* frame = GetDocument().GetFrame();
-  if (!frame)
-    return false;
-  return frame->GetContentSettingsClient()->AllowAutoplay(true);
-}
-
 void HTMLMediaElement::SetNetworkState(NetworkState state) {
   if (network_state_ == state)
     return;
@@ -4166,24 +4005,6 @@ EnumerationHistogram& HTMLMediaElement::ShowControlsHistogram() const {
   return histogram;
 }
 
-void HTMLMediaElement::OnVisibilityChangedForAutoplay(bool is_visible) {
-  if (!is_visible) {
-    if (can_autoplay_ && Autoplay()) {
-      PauseInternal();
-      can_autoplay_ = true;
-    }
-    return;
-  }
-
-  if (ShouldAutoplay()) {
-    paused_ = false;
-    ScheduleEvent(EventTypeNames::play);
-    ScheduleNotifyPlaying();
-
-    UpdatePlayState();
-  }
-}
-
 void HTMLMediaElement::ClearWeakMembers(Visitor* visitor) {
   if (!ThreadHeap::IsHeapObjectAlive(audio_source_node_)) {
     GetAudioSourceProvider().SetClient(nullptr);