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

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

Index: third_party/WebKit/Source/core/html/shadow/MediaControlsOrientationLockDelegate.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlsOrientationLockDelegate.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlsOrientationLockDelegate.cpp
index 624bb9d699665c15f24c9a04de2425fe35b4b8a1..f29c4c5e96961e78a9d3f10d87f856742bdb2348 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlsOrientationLockDelegate.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlsOrientationLockDelegate.cpp
@@ -64,12 +64,25 @@ class DummyScreenOrientationCallback : public WebLockOrientationCallback {
 MediaControlsOrientationLockDelegate::MediaControlsOrientationLockDelegate(
     HTMLVideoElement& video)
     : EventListener(CPPEventListenerType), m_videoElement(video) {
+  if (videoElement().isConnected())
+    attach();
+}
+
+void MediaControlsOrientationLockDelegate::attach() {
   document().addEventListener(EventTypeNames::fullscreenchange, this, true);
   videoElement().addEventListener(EventTypeNames::webkitfullscreenchange, this,
                                   true);
   videoElement().addEventListener(EventTypeNames::loadedmetadata, this, true);
 }
 
+void MediaControlsOrientationLockDelegate::detach() {
+  document().removeEventListener(EventTypeNames::fullscreenchange, this, true);
+  videoElement().removeEventListener(EventTypeNames::webkitfullscreenchange,
+                                     this, true);
+  videoElement().removeEventListener(EventTypeNames::loadedmetadata, this,
+                                     true);
+}
+
 bool MediaControlsOrientationLockDelegate::operator==(
     const EventListener& other) const {
   return this == &other;