Prefer ContextClient mixin over manual ExecutionContext handling.

third_party/WebKit/Source/modules/mediasource/SourceBufferList.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 12 matching lines @@
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "modules/mediasource/SourceBufferList.h"
 
-#include "core/dom/ExecutionContext.h"
 #include "core/events/GenericEventQueue.h"
 #include "modules/EventModules.h"
 #include "modules/mediasource/SourceBuffer.h"
 
 namespace blink {
 
 SourceBufferList::SourceBufferList(ExecutionContext* context,
                                    GenericEventQueue* asyncEventQueue)
-    : m_executionContext(context), m_asyncEventQueue(asyncEventQueue) {}
+    : ContextClient(context), m_asyncEventQueue(asyncEventQueue) {}
 
 SourceBufferList::~SourceBufferList() {}
 
 void SourceBufferList::add(SourceBuffer* buffer) {
   m_list.push_back(buffer);
   scheduleEvent(EventTypeNames::addsourcebuffer);
 }
 
 void SourceBufferList::insert(size_t position, SourceBuffer* buffer) {
   m_list.insert(position, buffer);
@@ skipping 19 matching lines @@
   Event* event = Event::create(eventName);
   event->setTarget(this);
 
   m_asyncEventQueue->enqueueEvent(event);
 }
 
 const AtomicString& SourceBufferList::interfaceName() const {
   return EventTargetNames::SourceBufferList;
 }
 
-ExecutionContext* SourceBufferList::getExecutionContext() const {
-  return m_executionContext;
-}
-
 DEFINE_TRACE(SourceBufferList) {
-  visitor->trace(m_executionContext);
   visitor->trace(m_asyncEventQueue);
   visitor->trace(m_list);
   EventTargetWithInlineData::trace(visitor);
+  ContextClient::trace(visitor);
 }
 
 }  // namespace blink