Submit CompositorFrame from worker

third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-commit-worker.html

+<!DOCTYPE>
+<canvas id="canvas2D" width="50" height="50" background-color="red"></canvas>
+<canvas id="canvas2Dexpected" width="50" height="50" background-color="green"></canvas>
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script id="myWorker" type="text/worker">
+self.onmessage = function(e) {
+var transferredOffscreenCanvas = e.data.data;
+var offscreen2d = transferredOffscreenCanvas.getContext("2d");
+offscreen2d.commit();
+self.postMessage("");
+};
+</script>
+<script>
+function makeWorker(script) {
+   var blob = new Blob([script]);
+   return new Worker(URL.createObjectURL(blob));
+}
+
+var expectedDataURL = document.getElementById("canvas2Dexpected").toDataURL();
+var actualDataURL;
+async_test(function() {
+    var canvas2D = document.getElementById("canvas2D");
+    var offscreenCanvas = canvas2D.transferControlToOffscreen();
+    var worker = makeWorker(document.getElementById("myWorker").textContent);
+    worker.onmessage = this.step_func(function (e) {
+        actualDataURL = canvas2D.toDataURL();
+        assert_equals(actualDataURL, expectedDataURL,

[Justin Novosad, 2016/09/07 21:40:15]

I don't understand how this verifies anything about the success to the call to
commit.  Come to think of it, calling toDataURL on a canvas that has transferred
control should probably throw an exception.

[xlai (Olivia), 2016/09/08 15:27:15]

Changing this test by using ref test again. I'll consolidate those 
transferred control canvas's functions that should throw exception
and upload another patch.

On 2016/09/07 21:40:15, Justin Novosad wrote:

+                "Expecting dataURL of " + expectedDataURL + "but got " + actualDataURL);
+        this.done();
+    });
+    worker.postMessage({data: offscreenCanvas}, [offscreenCanvas]);
+}, "Calling OffscreenCanvas.commit() on worker");
+
+
+
+</script>