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

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

Index: third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
index 7d2034368e868ae6caf1f848d5be7eb40a107a9a..76d680d18cee696b52edf93407031d4a34e33727 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
@@ -14,6 +14,18 @@ namespace blink {
 MediaControlsMediaEventListener::MediaControlsMediaEventListener(
     MediaControls* mediaControls)
     : EventListener(CPPEventListenerType), m_mediaControls(mediaControls) {
+  // These events are always active because they are needed in order to attach
+  // or detach the whole controls.
+  mediaElement().addEventListener(EventTypeNames::DOMNodeInsertedIntoDocument,
+                                  this, false);
+  mediaElement().addEventListener(EventTypeNames::DOMNodeRemovedFromDocument,
+                                  this, false);
+
+  if (mediaElement().isConnected())
+    attach();
+}
+
+void MediaControlsMediaEventListener::attach() {
   mediaElement().addEventListener(EventTypeNames::volumechange, this, false);
   mediaElement().addEventListener(EventTypeNames::focusin, this, false);
   mediaElement().addEventListener(EventTypeNames::timeupdate, this, false);
@@ -37,6 +49,16 @@ MediaControlsMediaEventListener::MediaControlsMediaEventListener(
   textTracks->addEventListener(EventTypeNames::removetrack, this, false);
 }
 
+void MediaControlsMediaEventListener::detach() {
+  m_mediaControls->document().removeEventListener(
+      EventTypeNames::fullscreenchange, this, false);
+
+  TextTrackList* textTracks = mediaElement().textTracks();
+  textTracks->removeEventListener(EventTypeNames::addtrack, this, false);
+  textTracks->removeEventListener(EventTypeNames::change, this, false);
+  textTracks->removeEventListener(EventTypeNames::removetrack, this, false);
+}
+
 bool MediaControlsMediaEventListener::operator==(
     const EventListener& other) const {
   return this == &other;
@@ -49,6 +71,14 @@ HTMLMediaElement& MediaControlsMediaEventListener::mediaElement() {
 void MediaControlsMediaEventListener::handleEvent(
     ExecutionContext* executionContext,
     Event* event) {
+  if (event->type() == EventTypeNames::DOMNodeInsertedIntoDocument) {
+    m_mediaControls->onInsertedIntoDocument();
+    return;
+  }
+  if (event->type() == EventTypeNames::DOMNodeRemovedFromDocument) {
+    m_mediaControls->onRemovedFromDocument();
+    return;
+  }
   if (event->type() == EventTypeNames::volumechange) {
     m_mediaControls->onVolumeChange();
     return;