Add more informative messages for DOM exceptions.

Source/modules/webaudio/DefaultAudioDestinationNode.cpp

 /*
  * Copyright (C) 2011, 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 10 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #if ENABLE(WEB_AUDIO)
 
 #include "modules/webaudio/DefaultAudioDestinationNode.h"
 
+#include "bindings/v8/ExceptionMessages.h"
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/platform/Logging.h"
 #include "wtf/MainThread.h"
 
 const unsigned EnabledInputChannels = 2;
 
 namespace WebCore {
 
 DefaultAudioDestinationNode::DefaultAudioDestinationNode(AudioContext* context)
@@ skipping 71 matching lines @@
 
 void DefaultAudioDestinationNode::setChannelCount(unsigned long channelCount, ExceptionState& es)
 {
     // The channelCount for the input to this node controls the actual number of channels we
     // send to the audio hardware. It can only be set depending on the maximum number of
     // channels supported by the hardware.
 
     ASSERT(isMainThread());
 
     if (!maxChannelCount() || channelCount > maxChannelCount()) {
-        es.throwUninformativeAndGenericDOMException(InvalidStateError);
+        es.throwDOMException(
+            InvalidStateError,
+            ExceptionMessages::failedToSet(
+                "channelCount",
+                "AudioDestinationNode",
+                "channel count (" + String::number(channelCount)
+                + ") must be between 1 and "
+                + String::number(maxChannelCount()) + "."));
         return;
     }
 
     unsigned long oldChannelCount = this->channelCount();
     AudioNode::setChannelCount(channelCount, es);
 
     if (!es.hadException() && this->channelCount() != oldChannelCount && isInitialized()) {
         // Re-create destination.
         m_destination->stop();
         createDestination();
         m_destination->start();
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)