Prefer ContextClient mixin over manual ExecutionContext handling.

third_party/WebKit/Source/modules/mediasource/SourceBufferList.h

 /*
  * 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 13 matching lines @@
  * 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.
  */
 
 #ifndef SourceBufferList_h
 #define SourceBufferList_h
 
+#include "core/dom/ExecutionContext.h"
 #include "modules/EventTargetModules.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class SourceBuffer;
 class GenericEventQueue;
 
-class SourceBufferList final : public EventTargetWithInlineData {
+class SourceBufferList final : public EventTargetWithInlineData,
+                               public ContextClient {
   DEFINE_WRAPPERTYPEINFO();
+  USING_GARBAGE_COLLECTED_MIXIN(SourceBufferList);
 
  public:
   static SourceBufferList* create(ExecutionContext* context,
                                   GenericEventQueue* asyncEventQueue) {
     return new SourceBufferList(context, asyncEventQueue);
   }
   ~SourceBufferList() override;
 
   unsigned length() const { return m_list.size(); }
 
   DEFINE_ATTRIBUTE_EVENT_LISTENER(addsourcebuffer);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(removesourcebuffer);
 
   SourceBuffer* item(unsigned index) const {
     return (index < m_list.size()) ? m_list[index].get() : 0;
   }
 
   void add(SourceBuffer*);
   void insert(size_t position, SourceBuffer*);
   void remove(SourceBuffer*);
   size_t find(SourceBuffer* buffer) { return m_list.find(buffer); }
   bool contains(SourceBuffer* buffer) {
     return m_list.find(buffer) != kNotFound;
   }
   void clear();
 
   // EventTarget interface
   const AtomicString& interfaceName() const override;
-  ExecutionContext* getExecutionContext() const override;
+  ExecutionContext* getExecutionContext() const override {
+    return ContextClient::getExecutionContext();
+  }
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   SourceBufferList(ExecutionContext*, GenericEventQueue*);
 
   void scheduleEvent(const AtomicString&);
 
-  Member<ExecutionContext> m_executionContext;
   Member<GenericEventQueue> m_asyncEventQueue;
 
   HeapVector<Member<SourceBuffer>> m_list;
 };
 
 }  // namespace blink
 
 #endif  // SourceBufferList_h