Move the exception logic to the AudioNode creator

third_party/WebKit/Source/modules/webaudio/GainNode.cpp

 /*
  * Copyright (C) 2010, 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 96 matching lines @@
         // This will propagate the channel count to any nodes connected further downstream in the graph.
         output(0).setNumberOfChannels(numberOfChannels);
         initialize();
     }
 
     AudioHandler::checkNumberOfChannelsForInput(input);
 }
 
 // ----------------------------------------------------------------
 
-GainNode::GainNode(AbstractAudioContext& context, float sampleRate)
+GainNode::GainNode(AbstractAudioContext& context)
     : AudioNode(context)
     , m_gain(AudioParam::create(context, ParamTypeGainGain, 1.0))
 {
-    setHandler(GainHandler::create(*this, sampleRate, m_gain->handler()));
+    setHandler(GainHandler::create(*this, context.sampleRate(), m_gain->handler()));
 }
 
-GainNode* GainNode::create(AbstractAudioContext& context, float sampleRate)
+GainNode* GainNode::create(AbstractAudioContext& context, ExceptionState& exceptionState)
 {
-    return new GainNode(context, sampleRate);
+    ASSERT(isMainThread());

[hongchan, 2016/05/13 01:20:12]

DCHECK.

[Raymond Toy, 2016/05/20 23:12:00]

Done.

+
+    if (context.isContextClosed()) {
+        context.throwExceptionForClosedState(exceptionState);
+        return nullptr;
+    }
+
+    return new GainNode(context);
 }
 
 AudioParam* GainNode::gain() const
 {
     return m_gain;
 }
 
 DEFINE_TRACE(GainNode)
 {
     visitor->trace(m_gain);
     AudioNode::trace(visitor);
 }
 
 } // namespace blink