Web Audio: Don't create unnecessary DelayNode object.

Source/modules/webaudio/DelayNode.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 17 matching lines @@
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "wtf/MathExtras.h"
 
 namespace blink {
 
 const double maximumAllowedDelayTime = 180;
 
-DelayNode::DelayNode(AudioContext* context, float sampleRate, double maxDelayTime, ExceptionState& exceptionState)
+DelayNode::DelayNode(AudioContext* context, float sampleRate, double maxDelayTime)
     : AudioBasicProcessorNode(NodeTypeDelay, context, sampleRate)

[haraken, 2015/03/20 13:42:01]

  , m_processor(new DelayProcessor(context, sampleRate, 1, maxDelayTime))

might be a bit better.

 {
+    m_processor = new DelayProcessor(context, sampleRate, 1, maxDelayTime);
+}
+
+DelayNode* DelayNode::create(AudioContext* context, float sampleRate, double maxDelayTime, ExceptionState& exceptionState)
+{
     if (maxDelayTime <= 0 || maxDelayTime >= maximumAllowedDelayTime) {
         exceptionState.throwDOMException(
             NotSupportedError,
             "max delay time (" + String::number(maxDelayTime)
             + ") must be between 0 and " + String::number(maximumAllowedDelayTime)
             + ", exclusive.");
-        return;
+        return nullptr;
     }
-    m_processor = new DelayProcessor(context, sampleRate, 1, maxDelayTime);
+    return new DelayNode(context, sampleRate, maxDelayTime);
 }
 
 AudioParam* DelayNode::delayTime()
 {
     return delayProcessor()->delayTime();
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)