[v8 gc] Introduce a base class for all objects that can have pending activity

third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 81 matching lines @@
 } // namespace
 
 SourceBuffer* SourceBuffer::create(PassOwnPtr<WebSourceBuffer> webSourceBuffer, MediaSource* source, GenericEventQueue* asyncEventQueue)
 {
     SourceBuffer* sourceBuffer = new SourceBuffer(webSourceBuffer, source, asyncEventQueue);
     sourceBuffer->suspendIfNeeded();
     return sourceBuffer;
 }
 
 SourceBuffer::SourceBuffer(PassOwnPtr<WebSourceBuffer> webSourceBuffer, MediaSource* source, GenericEventQueue* asyncEventQueue)
-    : ActiveDOMObject(source->getExecutionContext())
+    : ActiveScriptWrappable(this)
+    , ActiveDOMObject(source->getExecutionContext())
     , m_webSourceBuffer(webSourceBuffer)
     , m_source(source)
     , m_trackDefaults(TrackDefaultList::create())
     , m_asyncEventQueue(asyncEventQueue)
     , m_mode(segmentsKeyword())
     , m_updating(false)
     , m_timestampOffset(0)
     , m_appendWindowStart(0)
     , m_appendWindowEnd(std::numeric_limits<double>::infinity())
     , m_firstInitializationSegmentReceived(false)
@@ skipping 757 matching lines @@
     visitor->trace(m_asyncEventQueue);
     visitor->trace(m_appendBufferAsyncPartRunner);
     visitor->trace(m_removeAsyncPartRunner);
     visitor->trace(m_appendStreamAsyncPartRunner);
     visitor->trace(m_stream);
     RefCountedGarbageCollectedEventTargetWithInlineData<SourceBuffer>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink