Use EventHandler type instead of EventListener for event handler attributes

Source/modules/webaudio/AudioContext.idl

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple 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:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 59 matching lines @@
     [RaisesException] ScriptProcessorNode createScriptProcessor(unsigned long bufferSize, optional unsigned long numberOfInputChannels, optional unsigned long numberOfOutputChannels);
     OscillatorNode createOscillator();
     [RaisesException] PeriodicWave createPeriodicWave(Float32Array real, Float32Array imag);
 
     // Channel splitting and merging
     [RaisesException] ChannelSplitterNode createChannelSplitter(optional unsigned long numberOfOutputs);
     [RaisesException] ChannelMergerNode createChannelMerger(optional unsigned long numberOfInputs);
 
     // Offline rendering
     // void prepareOfflineBufferRendering(unsigned long numberOfChannels, unsigned long numberOfFrames, float sampleRate);
-    attribute EventListener oncomplete;
+    attribute EventHandler oncomplete;
     void startRendering();
 
     [MeasureAs=LegacyWebAudio, ImplementedAs=createGain] GainNode createGainNode();
     [MeasureAs=LegacyWebAudio, ImplementedAs=createDelay, RaisesException] DelayNode createDelayNode(optional double maxDelayTime);
 
     [MeasureAs=LegacyWebAudio, ImplementedAs=createScriptProcessor, RaisesException] ScriptProcessorNode createJavaScriptNode(unsigned long bufferSize, optional unsigned long numberOfInputChannels, optional unsigned long numberOfOutputChannels);
 
 };