Media: fix memory leak because of the document holding on an EventListener.

third_party/WebKit/Source/core/html/shadow/MediaControls.cpp

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Google 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 133 matching lines @@
                                this,
                                &MediaControls::hideMediaControlsTimerFired),
       m_hideTimerBehaviorFlags(IgnoreNone),
       m_isMouseOverControls(false),
       m_isPausedForScrubbing(false),
       m_panelWidthChangedTimer(TaskRunnerHelper::get(TaskType::UnspecedTimer,
                                                      &mediaElement.document()),
                                this,
                                &MediaControls::panelWidthChangedTimerFired),
       m_panelWidth(0),
-      m_keepShowingUntilTimerFires(false) {}
+      m_keepShowingUntilTimerFires(false) {
+        LOG(INFO) << "MediaControls ctor";
+      }
 
 MediaControls* MediaControls::create(HTMLMediaElement& mediaElement,
                                      ShadowRoot& shadowRoot) {
+  // TRACE_EVENT0("Blink", "CreateControls");
+
   MediaControls* controls = new MediaControls(mediaElement);
   controls->setShadowPseudoId(AtomicString("-webkit-media-controls"));
   controls->initializeControls();
   controls->reset();
 
   // Initialize the orientation lock when going fullscreen feature.
   if (RuntimeEnabledFeatures::videoFullscreenOrientationLockEnabled() &&
       mediaElement.isHTMLVideoElement()) {
     controls->m_orientationLockDelegate =
         new MediaControlsOrientationLockDelegate(
             toHTMLVideoElement(mediaElement));
   }
 
   shadowRoot.appendChild(controls);
   return controls;
 }
 
+MediaControls::~MediaControls() {
+  LOG(INFO) << "~MediaControls";
+}
+
 // The media controls DOM structure looks like:
 //
 // MediaControls
 //     (-webkit-media-controls)
 // +-MediaControlOverlayEnclosureElement
 // |    (-webkit-media-controls-overlay-enclosure)
 // | +-MediaControlOverlayPlayButtonElement
 // | |    (-webkit-media-controls-overlay-play-button)
 // | | {if mediaControlsOverlayPlayButtonEnabled}
 // | \-MediaControlCastButtonElement
@@ skipping 185 matching lines @@
   onTextTracksAddedOrRemoved();
 
   m_fullscreenButton->setIsWanted(shouldShowFullscreenButton(mediaElement()));
 
   refreshCastButtonVisibilityWithoutUpdate();
 
   m_downloadButton->setIsWanted(
       m_downloadButton->shouldDisplayDownloadButton());
 }
 
+void MediaControls::detach() {
+  m_windowEventListener->stop();
+  m_mediaEventListener->detach();
+  if (m_orientationLockDelegate)
+    m_orientationLockDelegate->detach();
+}
+
 LayoutObject* MediaControls::layoutObjectForTextTrackLayout() {
   return m_panel->layoutObject();
 }
 
 void MediaControls::show() {
   makeOpaque();
   m_panel->setIsWanted(true);
   m_panel->setIsDisplayed(true);
   if (m_overlayPlayButton)
     m_overlayPlayButton->updateDisplayType();
@@ skipping 560 matching lines @@
 void MediaControls::hideAllMenus() {
   m_windowEventListener->stop();
 
   if (m_overflowList->isWanted())
     m_overflowList->setIsWanted(false);
   if (m_textTrackList->isWanted())
     m_textTrackList->setVisible(false);
 }
 
 DEFINE_TRACE(MediaControls) {
+  LOG(INFO) << "MediaControls::trace";
   visitor->trace(m_mediaElement);
   visitor->trace(m_panel);
   visitor->trace(m_overlayPlayButton);
   visitor->trace(m_overlayEnclosure);
   visitor->trace(m_playButton);
   visitor->trace(m_currentTimeDisplay);
   visitor->trace(m_timeline);
   visitor->trace(m_muteButton);
   visitor->trace(m_volumeSlider);
   visitor->trace(m_toggleClosedCaptionsButton);
   visitor->trace(m_fullscreenButton);
   visitor->trace(m_downloadButton);
   visitor->trace(m_durationDisplay);
   visitor->trace(m_enclosure);
   visitor->trace(m_textTrackList);
   visitor->trace(m_overflowMenu);
   visitor->trace(m_overflowList);
   visitor->trace(m_castButton);
   visitor->trace(m_overlayCastButton);
   visitor->trace(m_mediaEventListener);
   visitor->trace(m_windowEventListener);
   visitor->trace(m_orientationLockDelegate);
   HTMLDivElement::trace(visitor);
 }
 
 }  // namespace blink