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diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/rendering/negative-one-index.html b/dom/canvas/test/webgl-conf/checkout/conformance/rendering/negative-one-index.html
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index 0000000000..69a59940a8
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+++ b/dom/canvas/test/webgl-conf/checkout/conformance/rendering/negative-one-index.html
@@ -0,0 +1,98 @@
+<!--
+Copyright (c) 2019 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">
+<title>-1 Index Rendering Test</title>
+<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>
+<canvas id="example" width="50" height="50">
+</canvas>
+<div id="description"></div>
+<div id="console"></div>
+<script id="vshader" type="x-shader/x-vertex">
+attribute vec4 vPosition;
+void main()
+{
+    gl_Position = vPosition;
+}
+</script>
+
+<script id="fshader" type="x-shader/x-fragment">
+void main()
+{
+    gl_FragColor = vec4(0.0,1.0,0.0,1.0);
+}
+</script>
+
+<script>
+"use strict";
+function init()
+{
+    description(document.title);
+
+    var wtu = WebGLTestUtils;
+    var gl = wtu.create3DContext("example");
+    var contextVersion = wtu.getDefault3DContextVersion();
+    var program = wtu.setupProgram(gl, ["vshader", "fshader"], ["vPosition"]);
+
+    var vertexObject = gl.createBuffer();
+    gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
+    var vertexData = new Float32Array(65536 * 3);
+    vertexData[0 * 3 + 0] = 0.0;
+    vertexData[0 * 3 + 1] = 0.5;
+    vertexData[0 * 3 + 2] = 0.0;
+    vertexData[1 * 3 + 0] = -0.5;
+    vertexData[1 * 3 + 1] = -0.5;
+    vertexData[1 * 3 + 2] = 0.0;
+    vertexData[65535 * 3 + 0] = 0.5;
+    vertexData[65535 * 3 + 1] = -0.5;
+    vertexData[65535 * 3 + 2] = 0.0;
+    gl.bufferData(gl.ARRAY_BUFFER, vertexData, gl.STATIC_DRAW);
+    gl.enableVertexAttribArray(0);
+    gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);
+
+    var indices = new Uint16Array([0, 1, -1]);
+    var indexBuffer = gl.createBuffer();
+    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
+    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
+
+    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
+    gl.drawElements(gl.TRIANGLES, 3, gl.UNSIGNED_SHORT, 0);
+
+    if (contextVersion <= 1) {
+        // This should render a green triangle in the middle of the canvas.
+        // Some implementations may incorrectly interpret the -1 index as
+        // a primitive restart and not render anything.
+
+        // Test several locations
+        // First line should be all black
+        wtu.checkCanvasRect(gl, 0, 0, 50, 1, [0, 0, 0, 0]);
+
+        // Line 15 should be green for at least 10 pixels starting from row 20
+        wtu.checkCanvasRect(gl, 20, 15, 10, 1, [0, 255, 0, 255]);
+
+        // Last line should be all black
+        wtu.checkCanvasRect(gl, 0, 49, 50, 1, [0, 0, 0, 0]);
+    } else {
+        // For WebGL 2, PRIMITIVE_RESTART_FIXED_INDEX is always enabled.
+        // Nothing should be drawn on the canvas.
+        wtu.checkCanvasRect(gl, 0, 0, 50, 50, [0, 0, 0, 0]);
+    }
+}
+
+init();
+var successfullyParsed = true;
+</script>
+<script src="../../js/js-test-post.js"></script>
+
+</body>
+</html>