WebAudio createBuffer should throw error with 0 channels.

LayoutTests/webaudio/dom-exceptions.html

Index: LayoutTests/webaudio/dom-exceptions.html
diff --git a/LayoutTests/webaudio/dom-exceptions.html b/LayoutTests/webaudio/dom-exceptions.html
index 45c9eacfa19b01c9952f70adb7cace395a3c613b..db8ef1530cfc01daf7de33304c4d462840d1d981 100644
--- a/LayoutTests/webaudio/dom-exceptions.html
+++ b/LayoutTests/webaudio/dom-exceptions.html
@@ -32,6 +32,7 @@ function runTest() {
 
     // Invalid number of channels: NotSupportedError
     shouldThrow("context.createBuffer(99, 1, context.sampleRate)");
+    shouldThrow("context.createBuffer(0, 1, context.sampleRate)");
     // Invalid sample rate: NotSupportedError
     shouldThrow("context.createBuffer(1, 1, 1)");
     shouldThrow("context.createBuffer(1, 1, 1e6)");