Web Audio: Don't create unnecessary DelayNode object.

Source/modules/webaudio/DelayNode.cpp

Index: Source/modules/webaudio/DelayNode.cpp
diff --git a/Source/modules/webaudio/DelayNode.cpp b/Source/modules/webaudio/DelayNode.cpp
index 65b6a88d8b3e1e75f0f531dbc853a51792f8ff4b..53b18f03862c988ddbef05303b76fa5f595d0475 100644
--- a/Source/modules/webaudio/DelayNode.cpp
+++ b/Source/modules/webaudio/DelayNode.cpp
@@ -35,18 +35,23 @@ 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()