Add more informative messages for DOM exceptions.

Source/modules/webaudio/OfflineAudioContext.cpp

 /*
  * Copyright (C) 2012, 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/OfflineAudioContext.h"
 
+#include "bindings/v8/ExceptionMessages.h"
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ScriptExecutionContext.h"
 
 namespace WebCore {
 
 PassRefPtr<OfflineAudioContext> OfflineAudioContext::create(ScriptExecutionContext* context, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState& es)
 {
     // FIXME: add support for workers.
     if (!context || !context->isDocument()) {
-        es.throwUninformativeAndGenericDOMException(NotSupportedError);
+        es.throwDOMException(
+            NotSupportedError,
+            ExceptionMessages::failedToConstruct("OfflineAudioContext"));
         return 0;
     }
 
     Document* document = toDocument(context);
 
-    if (numberOfChannels > 10 || !isSampleRateRangeGood(sampleRate)) {
-        es.throwUninformativeAndGenericDOMException(SyntaxError);
+    if (numberOfChannels > 10) {
+        es.throwDOMException(
+            SyntaxError,
+            ExceptionMessages::failedToConstruct(
+                "OfflineAudioContext",
+                "number of channels (" + String::number(numberOfChannels) + ") exceeds maximum (10)."));
         return 0;
     }
 
+    if (!isSampleRateRangeGood(sampleRate)) {
+        es.throwDOMException(
+            SyntaxError,
+            ExceptionMessages::failedToConstruct(
+                "OfflineAudioContext",
+                "sample rate (" + String::number(sampleRate) + ") must be in the range 44100-96000 Hz."));
+        return 0;
+    }
+
     RefPtr<OfflineAudioContext> audioContext(adoptRef(new OfflineAudioContext(document, numberOfChannels, numberOfFrames, sampleRate)));
     audioContext->suspendIfNeeded();
     return audioContext.release();
 }
 
 OfflineAudioContext::OfflineAudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate)
     : AudioContext(document, numberOfChannels, numberOfFrames, sampleRate)
 {
     ScriptWrappable::init(this);
 }
 
 OfflineAudioContext::~OfflineAudioContext()
 {
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)