Output silence if the MediaElementAudioSourceNode has a different origin

LayoutTests/http/tests/security/resources/webaudio/media-element-audio-source-node-test.js

+// Test MediaStreamAudioSourceNode's with different URLs.
+//
+var context = 0;
+var lengthInSeconds = 1;
+var sampleRate = 44100;
+var source = 0;
+var audio = 0;
+
+// Create an MediaElementSource node with the given |url| and connect it to webaudio.
+// |oncomplete| is given the completion event to check the result.
+function runTest (url, oncomplete, tester)
+{
+    if (window.testRunner) {
+        testRunner.dumpAsText();
+        testRunner.waitUntilDone();
+    }
+
+    window.jsTestIsAsync = true;
+
+    context = new OfflineAudioContext(1, sampleRate * lengthInSeconds, sampleRate);
+
+    audio = document.createElement('audio');
+
+    if (tester) {
+        tester();
+    } else {
+        audio.src = url;
+    }
+
+    source = context.createMediaElementSource(audio);
+    source.connect(context.destination);
+
+    audio.addEventListener("playing", function(e) {
+            context.startRendering();
+        });
+
+    context.oncomplete = function(e) {
+        checkResult(e);
+        finishJSTest();
+    }
+
+    audio.play();
+}