Add more informative messages for DOM exceptions.

Source/modules/webaudio/AnalyserNode.cpp

Index: Source/modules/webaudio/AnalyserNode.cpp
diff --git a/Source/modules/webaudio/AnalyserNode.cpp b/Source/modules/webaudio/AnalyserNode.cpp
index 128840ef9b0e2787c49a12668f9f3992613f2fc4..bacfbdaee5bc5045e54df40aa5b400b1569d2010 100644
--- a/Source/modules/webaudio/AnalyserNode.cpp
+++ b/Source/modules/webaudio/AnalyserNode.cpp
@@ -28,6 +28,7 @@
 
 #include "modules/webaudio/AnalyserNode.h"
 
+#include "bindings/v8/ExceptionMessages.h"
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "modules/webaudio/AudioNodeInput.h"
@@ -75,8 +76,14 @@ void AnalyserNode::reset()
 
 void AnalyserNode::setFftSize(unsigned size, ExceptionState& es)
 {
-    if (!m_analyser.setFftSize(size))
-        es.throwUninformativeAndGenericDOMException(NotSupportedError);
+    if (!m_analyser.setFftSize(size)) {
+        es.throwDOMException(
+            NotSupportedError,
+            ExceptionMessages::failedToSet(
+                "fftSize",
+                "AnalyserNode",
+                "FFT size is out of range or not a power of two."));
+    }
 }
 
 } // namespace WebCore