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<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/html/canvas/resources/canvas-tests.js"></script>
<link rel="help" href="https://html.spec.whatwg.org/#offscreencontext2d-commit">
<script>
function verifyPlaceholder(placeholder, expectedR, expectedG, expectedB, expectedA, expectedClrStr)
{
var canvas = document.createElement('canvas');
canvas.width = canvas.height = 10;
var ctx = canvas.getContext('2d');
ctx.drawImage(placeholder, 0, 0);
_assertPixel(canvas, 5,5, expectedR, expectedG, expectedB, expectedA);
}
async_test(function(t) {
var placeholder = document.createElement('canvas');
placeholder.width = placeholder.height = 10;
var offscreenCanvas = placeholder.transferControlToOffscreen();
var ctx = offscreenCanvas.getContext('2d');
ctx.fillStyle = "#0f0";
ctx.fillRect(0, 0, 10, 10);
// commit() propagation is taken care of by an async task, which means the
// place holder contents should still be transparent black at this moment.
verifyPlaceholder(placeholder, 0,0,0,0, "0,0,0,0");
// Set timeout acts as a sync barrier to allow commit to propagate
t.step_timeout(function() {
verifyPlaceholder(placeholder, 0,255,0,255, "0,255,0,255");
t.done();
}, 0);
}, "Test that calling OffscreenCanvas's commit pushes its contents to its placeholder.");
test(function() {
var offscreenCanvas = new OffscreenCanvas(10, 10);
var ctx = offscreenCanvas.getContext('2d');
ctx.fillStyle = "#0f0";
ctx.fillRect(0, 0, 10, 10);
ctx.commit();
}, "Test that calling commit on an OffscreenCanvas that is not transferred from a HTMLCanvasElement is a noop.");
</script>
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