Add more informative messages for DOM exceptions.

Source/modules/webaudio/AudioBuffer.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
@@ skipping 50 matching lines @@
 
     // Scalar gain
     double gain() const { return m_gain; }
     void setGain(double gain) { m_gain = gain; }
 
     // Because an AudioBuffer has a JavaScript wrapper, which will be garbage collected, it may take awhile for this object to be deleted.
     // releaseMemory() can be called when the AudioContext goes away, so we can release the memory earlier than when the garbage collection happens.
     // Careful! Only call this when the page unloads, after the AudioContext is no longer processing.
     void releaseMemory();
 
+    static float minAllowedSampleRate();
+    static float maxAllowedSampleRate();
 protected:
     AudioBuffer(unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
     explicit AudioBuffer(AudioBus*);
 
     double m_gain; // scalar gain
     float m_sampleRate;
     size_t m_length;
 
     Vector<RefPtr<Float32Array> > m_channels;
 };
 
 } // namespace WebCore
 
 #endif // AudioBuffer_h