Detect change on video/viewport intersection when rendered remotely

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

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 110 matching lines @@
 using namespace HTMLNames;
 
 using WeakMediaElementSet = HeapHashSet<WeakMember<HTMLMediaElement>>;
 using DocumentElementSetMap =
     HeapHashMap<WeakMember<Document>, Member<WeakMediaElementSet>>;
 
 namespace {
 
 constexpr float kMostlyFillViewportThreshold = 0.85f;
 constexpr double kMostlyFillViewportBecomeStableSeconds = 5;
+constexpr double kCheckIntersectWhenPausedIntervalInSeconds = 2;

[miu, 2016/12/10 02:18:37]

If the "stable" check is 5 seconds, the timer interval should be something that
is zero modulo 5 seconds: Probably 1 second would be fine.

[xjz, 2016/12/12 18:58:45]

Done.

 
 enum MediaControlsShow {
   MediaControlsShowAttribute = 0,
   MediaControlsShowFullscreen,
   MediaControlsShowNoScript,
   MediaControlsShowNotShown,
   MediaControlsShowMax
 };
 
 String urlForLoggingMedia(const KURL& url) {
@@ skipping 222 matching lines @@
       ActiveScriptWrappable(this),
       ActiveDOMObject(&document),
       m_loadTimer(this, &HTMLMediaElement::loadTimerFired),
       m_progressEventTimer(this, &HTMLMediaElement::progressEventTimerFired),
       m_playbackProgressTimer(this,
                               &HTMLMediaElement::playbackProgressTimerFired),
       m_audioTracksTimer(this, &HTMLMediaElement::audioTracksTimerFired),
       m_viewportFillDebouncerTimer(
           this,
           &HTMLMediaElement::viewportFillDebouncerTimerFired),
+      m_checkIntersectionWhenPausedTimer(
+          this,
+          &HTMLMediaElement::checkIntersectionWhenPausedTimerFired),
       m_playedTimeRanges(),
       m_asyncEventQueue(GenericEventQueue::create(this)),
       m_playbackRate(1.0f),
       m_defaultPlaybackRate(1.0f),
       m_networkState(kNetworkEmpty),
       m_readyState(kHaveNothing),
       m_readyStateMaximum(kHaveNothing),
       m_volume(1.0f),
       m_lastSeekTime(0),
       m_previousProgressTime(std::numeric_limits<double>::max()),
@@ skipping 2864 matching lines @@
 
     if (!isPlaying) {
       // Set rate, muted before calling play in case they were set before the
       // media engine was setup.  The media engine should just stash the rate
       // and muted values since it isn't already playing.
       webMediaPlayer()->setRate(playbackRate());
       webMediaPlayer()->setVolume(effectiveMediaVolume());
       webMediaPlayer()->play();
     }
 
+    m_checkIntersectionWhenPausedTimer.stop();
     startPlaybackProgressTimer();
     m_playing = true;
   } else {  // Should not be playing right now
     if (isPlaying) {
       webMediaPlayer()->pause();
     }
 
     m_playbackProgressTimer.stop();
+    startCheckIntersectionWhenPausedTimer();
     m_playing = false;
     double time = currentTime();
     if (time > m_lastSeekTime)
       addPlayedRange(m_lastSeekTime, time);
   }
 
   if (layoutObject())
     layoutObject()->updateFromElement();
 }
 
 void HTMLMediaElement::stopPeriodicTimers() {
   m_progressEventTimer.stop();
   m_playbackProgressTimer.stop();
+  m_checkIntersectionWhenPausedTimer.stop();

[miu, 2016/12/10 02:18:37]

If you take my advice below, this extra stop() call here becomes unnecessary.

[xjz, 2016/12/12 18:58:45]

Done.

 }
 
 void HTMLMediaElement::
     clearMediaPlayerAndAudioSourceProviderClientWithoutLocking() {
   getAudioSourceProvider().setClient(nullptr);
   if (m_webMediaPlayer) {
     m_audioSourceProvider.wrap(nullptr);
     m_webMediaPlayer.reset();
   }
 }
@@ skipping 738 matching lines @@
 }
 
 DEFINE_TRACE(HTMLMediaElement::AudioClientImpl) {
   visitor->trace(m_client);
 }
 
 DEFINE_TRACE(HTMLMediaElement::AudioSourceProviderImpl) {
   visitor->trace(m_client);
 }
 
+void HTMLMediaElement::enableMonitorViewportIntersection(bool enable) {
+  m_enableMonitorViewportIntersection = enable;

[miu, 2016/12/10 02:18:37]

IMHO, this would all be simpler if we didn't have two different timers that
might call checkViewportIntersectionChanged(). Let's just have one and then:

1. Rename m_checkIntersectionWhenPausedTimer to just
m_checkViewportIntersectionTimer.

2. Get rid of the m_enableMonitorViewportIntersection boolean.

3. Only call start() or stop() on the timer from
enableMonitorViewportIntersection():

  void HTMLMediaElement::enableMonitorViewportIntersection(bool enable) {
    if (enable && !m_checkViewportIntersectionTimer.isActive())
      m_checkViewportIntersectionTimer.startRepeating(...);
    else if (!enable)
      m_checkViewportIntersectionTimer.stop();
  }

[xjz, 2016/12/12 18:58:45]

Done.

+}
+
 void HTMLMediaElement::checkViewportIntersectionChanged() {
-  // TODO(xjz): Early return if we not in tab mirroring.
+  if (!m_enableMonitorViewportIntersection)
+    return;
 
   IntersectionGeometry geometry(
       document().frame()->localFrameRoot()->document(), this, Vector<Length>(),
       IntersectionGeometry::ReportRootBounds::kShouldReportRootBounds);
   geometry.computeGeometry();
   IntRect intersectRect = geometry.intersectionIntRect();
   if (m_currentIntersectRect == intersectRect)
     return;
 
   m_currentIntersectRect = intersectRect;
@@ skipping 16 matching lines @@
   m_viewportFillDebouncerTimer.startOneShot(
       kMostlyFillViewportBecomeStableSeconds, BLINK_FROM_HERE);
 }
 
 void HTMLMediaElement::viewportFillDebouncerTimerFired(TimerBase*) {
   m_mostlyFillingViewport = true;
   if (m_webMediaPlayer)
     m_webMediaPlayer->becameDominantVisibleContent(m_mostlyFillingViewport);
 }
 
+void HTMLMediaElement::checkIntersectionWhenPausedTimerFired(TimerBase*) {
+  checkViewportIntersectionChanged();
+}
+
+void HTMLMediaElement::startCheckIntersectionWhenPausedTimer() {
+  if (m_checkIntersectionWhenPausedTimer.isActive())
+    return;
+
+  m_checkIntersectionWhenPausedTimer.startRepeating(
+      kCheckIntersectWhenPausedIntervalInSeconds, BLINK_FROM_HERE);
+}
+
 }  // namespace blink