AudioBufferSourceNode.buffer can only be set once.

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 3971cdf6f2a7a1187738bb113f7ae614ce9aa928..5918bd8d37ddff06fd3157a8927798238bebb9be 100644
--- a/LayoutTests/webaudio/dom-exceptions.html
+++ b/LayoutTests/webaudio/dom-exceptions.html
@@ -169,6 +169,9 @@ function runTest() {
     buffer = context.createBuffer(1,1, context.sampleRate);
     shouldNotThrow("source = context.createBufferSource()");
     shouldNotThrow("source.buffer = buffer");
+    // Setting the buffer twice will eventually throw an error, but for now, it's just a deprecation
+    // warning.
+    shouldNotThrow("source.buffer = context.createBuffer(1, 10, context.sampleRate)");
     shouldThrow("source.start(-1)");
     shouldThrow("source.start(Infinity)");
     shouldThrow("source.start(-Infinity)");