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

third_party/WebKit/Source/modules/mediasource/MediaSource.idl

 /*
  * 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 18 matching lines @@
  */
 
 // https://www.w3.org/TR/media-source/#idl-def-MediaSource
 
 enum EndOfStreamError {
     "network",
     "decode"
 };
 
 [
-    DependentLifetime,
+    ActiveScriptWrappable,
     Constructor,
     ConstructorCallWith=ExecutionContext,
+    DependentLifetime,
 ] interface MediaSource : EventTarget {
     // All the source buffers created by this object.
     readonly attribute SourceBufferList sourceBuffers;
 
     // Subset of sourceBuffers that provide data for the selected/enabled tracks.
     readonly attribute SourceBufferList activeSourceBuffers;
 
     [RaisesException=Setter] attribute unrestricted double duration;
 
     [RaisesException] SourceBuffer addSourceBuffer(DOMString type);
     [RaisesException] void removeSourceBuffer(SourceBuffer buffer);
 
     readonly attribute DOMString readyState;
 
     [RaisesException] void endOfStream(optional EndOfStreamError error);
 
     static boolean isTypeSupported (DOMString type);
 };