Signal exceptions if start/stop is called out-of-order or too many times.

Source/modules/webaudio/AudioNode.h

 /*
  * 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 71 matching lines @@
         NodeTypeEnd
     };
 
     enum ChannelCountMode {
         Max,
         ClampedMax,
         Explicit
     };
 
     NodeType nodeType() const { return m_nodeType; }
+    String nodeTypeName() const;
     void setNodeType(NodeType);
 
     // We handle our own ref-counting because of the threading issues and subtle nature of
     // how AudioNodes can continue processing (playing one-shot sound) after there are no more
     // JavaScript references to the object.
     enum RefType { RefTypeNormal, RefTypeConnection };
 
     // Can be called from main thread or context's audio thread.
     void ref(RefType refType = RefTypeNormal);
     void deref(RefType refType = RefTypeNormal);
@@ skipping 122 matching lines @@
 
 protected:
     unsigned m_channelCount;
     ChannelCountMode m_channelCountMode;
     AudioBus::ChannelInterpretation m_channelInterpretation;
 };
 
 } // namespace WebCore
 
 #endif // AudioNode_h