Reduce ActiveDOMObjects from modules/mediastream/

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

Index: third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.h
diff --git a/third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.h b/third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.h
index d47014a30441094f4d279e8ac3f47610fde0e7b2..2857ea3e13285e30a8877001cea3474462c9808e 100644
--- a/third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.h
+++ b/third_party/WebKit/Source/modules/mediastream/RTCDTMFSender.h
@@ -26,7 +26,7 @@
 #ifndef RTCDTMFSender_h
 #define RTCDTMFSender_h
 
-#include "core/dom/ActiveDOMObject.h"
+#include "core/dom/ContextLifecycleObserver.h"
 #include "modules/EventTargetModules.h"
 #include "platform/Timer.h"
 #include "public/platform/WebRTCDTMFSenderHandlerClient.h"
@@ -41,7 +41,7 @@ class WebRTCPeerConnectionHandler;
 class RTCDTMFSender final
     : public RefCountedGarbageCollectedEventTargetWithInlineData<RTCDTMFSender>
     , public WebRTCDTMFSenderHandlerClient
-    , public ActiveDOMObject {
+    , public ContextLifecycleObserver {
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(RTCDTMFSender);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RTCDTMFSender);
     DEFINE_WRAPPERTYPEINFO();
@@ -65,8 +65,7 @@ public:
     const AtomicString& interfaceName() const override;
     ExecutionContext* executionContext() const override;
 
-    // ActiveDOMObject
-    void stop() override;
+    void contextDestroyed() override;
 
     // Oilpan: need to eagerly finalize m_handler
     EAGERLY_FINALIZE();
@@ -87,8 +86,6 @@ private:
 
     OwnPtr<WebRTCDTMFSenderHandler> m_handler;
 
-    bool m_stopped;
-
     Timer<RTCDTMFSender> m_scheduledEventTimer;
     WillBeHeapVector<RefPtrWillBeMember<Event>> m_scheduledEvents;
 };