Reduce ActiveDOMObjects from modules/mediastream/

third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h

Index: third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h
index 90fec99a61aadcd0ad2a3c884a4f5485914b820f..f1829c6bf9c1b7890830a9f3d20f6fc0e0f0c7a7 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h
+++ b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.h
@@ -26,7 +26,7 @@
 #ifndef MediaStreamTrack_h
 #define MediaStreamTrack_h
 
-#include "core/dom/ActiveDOMObject.h"
+#include "core/dom/ContextLifecycleObserver.h"
 #include "modules/EventTargetModules.h"
 #include "modules/ModulesExport.h"
 #include "modules/mediastream/SourceInfo.h"
@@ -43,7 +43,7 @@ class MediaStreamTrackSourcesCallback;
 
 class MODULES_EXPORT MediaStreamTrack
     : public RefCountedGarbageCollectedEventTargetWithInlineData<MediaStreamTrack>
-    , public ActiveDOMObject
+    , public ContextLifecycleObserver
     , public MediaStreamSource::Observer {
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(MediaStreamTrack);
     USING_GARBAGE_COLLECTED_MIXIN(MediaStreamTrack);
@@ -83,9 +83,7 @@ public:
     const AtomicString& interfaceName() const override;
     ExecutionContext* executionContext() const override;
 
-    // ActiveDOMObject
     bool hasPendingActivity() const override;
-    void stop() override;
 
     PassOwnPtr<AudioSourceProvider> createWebAudioSource();
 
@@ -104,7 +102,6 @@ private:
     MediaStreamSource::ReadyState m_readyState;
     HeapHashSet<Member<MediaStream>> m_registeredMediaStreams;
     bool m_isIteratingRegisteredMediaStreams;
-    bool m_stopped;
     Member<MediaStreamComponent> m_component;
 };