AudioBufferSourceNode.buffer can only be set once.

LayoutTests/webaudio/audiobuffersource-channels.html

Index: LayoutTests/webaudio/audiobuffersource-channels.html
diff --git a/LayoutTests/webaudio/audiobuffersource-channels.html b/LayoutTests/webaudio/audiobuffersource-channels.html
index 1f7256b19f2211375625e46530907243b8756e1e..3098e60c66f6a16b7d18443473749409b016c70b 100644
--- a/LayoutTests/webaudio/audiobuffersource-channels.html
+++ b/LayoutTests/webaudio/audiobuffersource-channels.html
@@ -35,6 +35,7 @@ function runTest() {
     // Check that mono buffer can be set.
     try {
         var monoBuffer = context.createBuffer(1, 1024, context.sampleRate);
+        source = context.createBufferSource();

[hongchan, 2015/01/16 23:42:09]

This is something I am not comfortable with. Even thought the code is fully
functional, but the variable 'source' is defined globally and used for all the
test cases. I prefer to encapsulate each test from others.

I have seen a lot like this from tests which is written by crogers@, but am
quite not sure about it. I will  leave this up to you.

[Raymond Toy, 2015/01/17 00:03:16]

The global source is needed for the shouldThrow() stuff, but I can make the
other uses local vars.

[Raymond Toy, 2015/01/20 18:06:00]

Done.

         source.buffer = monoBuffer;
         testPassed("Mono buffer can be set.");
     } catch(e) {
@@ -44,6 +45,7 @@ function runTest() {
     // Check that stereo buffer can be set.
     try {
         var stereoBuffer = context.createBuffer(2, 1024, context.sampleRate);
+        source = context.createBufferSource();
         source.buffer = stereoBuffer;
         testPassed("Stereo buffer can be set.");
     } catch(e) {
@@ -54,6 +56,7 @@ function runTest() {
     for (var i = 3; i < 10; ++i) {
         try {
             var buffer = context.createBuffer(i, 1024, context.sampleRate);
+            source = context.createBufferSource();
             source.buffer = buffer;
             var message = i + " channels buffer can be set.";
             testPassed(message);