AudioContext.decodeAudioData returns a Promise

LayoutTests/webaudio/decode-audio-data-basic.html

Index: LayoutTests/webaudio/decode-audio-data-basic.html
diff --git a/LayoutTests/webaudio/decode-audio-data-basic.html b/LayoutTests/webaudio/decode-audio-data-basic.html
index d97e4c74bed44782c0fc096fc0bc643155358ac0..2452cf0f49af2677a0c20b1d6ffa7ce896eff103 100644
--- a/LayoutTests/webaudio/decode-audio-data-basic.html
+++ b/LayoutTests/webaudio/decode-audio-data-basic.html
@@ -18,12 +18,13 @@ window.jsTestIsAsync = true;
 
 var context = new AudioContext();
 
-try {
-    context.decodeAudioData(null, function(){}, function(){});
-    testFailed("decodeAudioData should raise exception when arraybuffer parameter is null.");
-} catch(e) {
-    testPassed("decodeAudioData raises exception correctly when arraybuffer parameter is null.");
-}
+context.decodeAudioData(null,
+    function () {
+      testFailed("decodeAudioData(null) did not invoke errorCallback.");
+    },
+    function (e) {
+      testPassed("decodeAudioData(null) invoked errorCallback correctly: " + e);
+    });
 
 var decodeCaseArray = [{url: "resources/media/24bit-44khz.wav", result: true},
                        {url: "resources/media/invalid-audio-file.txt", result: false}];