Revert of Reduce ActiveDOMObjects from core/

third_party/WebKit/Source/core/dom/MessagePort.h

Index: third_party/WebKit/Source/core/dom/MessagePort.h
diff --git a/third_party/WebKit/Source/core/dom/MessagePort.h b/third_party/WebKit/Source/core/dom/MessagePort.h
index 556ceeeeb038ab691aacdfbf9d07fc4b4d53c025..8e7f8083906dc0fa05df0154fd486a15df2d17c6 100644
--- a/third_party/WebKit/Source/core/dom/MessagePort.h
+++ b/third_party/WebKit/Source/core/dom/MessagePort.h
@@ -28,7 +28,7 @@
 #define MessagePort_h
 
 #include "core/CoreExport.h"
-#include "core/dom/ContextLifecycleObserver.h"
+#include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventListener.h"
 #include "core/events/EventTarget.h"
 #include "public/platform/WebMessagePortChannel.h"
@@ -57,7 +57,7 @@
 
 class CORE_EXPORT MessagePort
     : public RefCountedGarbageCollectedEventTargetWithInlineData<MessagePort>
-    , public ContextLifecycleObserver
+    , public ActiveDOMObject
     , public WebMessagePortChannelClient {
     DEFINE_WRAPPERTYPEINFO();
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(MessagePort);
@@ -86,11 +86,12 @@
     bool started() const { return m_started; }
 
     const AtomicString& interfaceName() const override;
-    ExecutionContext* executionContext() const override { return ContextLifecycleObserver::executionContext(); }
+    ExecutionContext* executionContext() const override { return ActiveDOMObject::executionContext(); }
     MessagePort* toMessagePort() override { return this; }
 
+    // ActiveDOMObject implementation.
     bool hasPendingActivity() const override;
-    void contextDestroyed() override { close(); }
+    void stop() override { close(); }
 
     void setOnmessage(PassRefPtrWillBeRawPtr<EventListener> listener)
     {