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diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/context/zero-sized-canvas.html b/dom/canvas/test/webgl-conf/checkout/conformance/context/zero-sized-canvas.html
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+++ b/dom/canvas/test/webgl-conf/checkout/conformance/context/zero-sized-canvas.html
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+<!--
+Copyright (c) 2020 The Khronos Group Inc.
+Use of this source code is governed by an MIT-style license that can be
+found in the LICENSE.txt file.
+-->
+
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<link rel="stylesheet" href="../../resources/js-test-style.css"/>
+<script src="../../js/js-test-pre.js"></script>
+<script src="../../js/webgl-test-utils.js"></script>
+</head>
+<body>
+<div id="description"></div>
+<div id="console"></div>
+<script>
+"use strict";
+
+// Global declarations so that "shouldBe" can eval with them:
+let gl;
+
+(function() {
+    description('Check that zero-sized canvases work with WebGL.');
+
+    testZero();
+
+    finishTest();
+})();
+
+function testZero() {
+    const canvas = document.createElement('canvas');
+    canvas.width = 0;
+    canvas.height = 0;
+    gl = WebGLTestUtils.create3DContext(canvas);
+
+    expectTrue(gl, `Context creation with ${canvas.width}x${canvas.height} canvas should succeed.`);
+    shouldBe('gl.drawingBufferWidth', '1');
+    shouldBe('gl.drawingBufferHeight', '1');
+    shouldBeFalse('gl.isContextLost()');
+
+    const version = gl.getParameter(gl.VERSION);
+    expectTrue(version && version.length, `getParameter() should return something.`);
+
+    debug('canvas.width = 2');
+    canvas.width = 2;
+    shouldBe('gl.drawingBufferWidth', '2');
+    shouldBeFalse('gl.isContextLost()');
+
+    debug('canvas.width = 0');
+    canvas.width = 0;
+    shouldBe('gl.drawingBufferWidth', '1');
+    shouldBeFalse('gl.isContextLost()');
+}
+
+</script>
+</body>
+</html>