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diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/renderbuffers/renderbuffer-initialization.html b/dom/canvas/test/webgl-conf/checkout/conformance/renderbuffers/renderbuffer-initialization.html
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index 0000000000..83406552bc
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@@ -0,0 +1,99 @@
+<!--
+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">
+<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="testbed" width="400" height="400" style="width: 40px; height: 40px;"></canvas>
+<div id="description"></div>
+<div id="console"></div>
+<script>
+"use strict";
+var wtu = WebGLTestUtils;
+description('Verify renderbuffers are initialized to 0 before being read in WebGL');
+
+var gl = wtu.create3DContext("testbed");
+if (!gl) {
+    testFailed('canvas.getContext() failed');
+} else {
+    // Set the clear color to green. It should never show up.
+    gl.clearColor(0, 1, 0, 1);
+
+    runTest(gl, gl.canvas.width, gl.canvas.height, 0);
+    runTest(gl, gl.canvas.width, gl.canvas.height, 1);
+    runTest(gl, gl.canvas.width, gl.canvas.height, 0);
+    runTest(gl, gl.canvas.width, gl.canvas.height, 1);
+
+    // Testing buffer clearing won't change the clear values.
+    var clearColor = gl.getParameter(gl.COLOR_CLEAR_VALUE);
+    shouldBe("clearColor", "[0, 1, 0, 1]");
+    wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no errors');
+}
+
+function runTest(gl, width, height, order)
+{
+    wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
+                        "internal buffers have been initialized to 0");
+
+    // fill the back buffer so we know that reading below happens from
+    // the renderbuffer.
+    gl.clear(gl.COLOR_BUFFER_BIT);
+
+    var fbo = gl.createFramebuffer();
+    gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
+    var colorbuffer = gl.createRenderbuffer();
+    gl.bindRenderbuffer(gl.RENDERBUFFER, colorbuffer);
+    switch (order) {
+      case 0:
+        allocStorage(width, height);
+        attachBuffer(colorbuffer);
+        break;
+      case 1:
+        attachBuffer(colorbuffer);
+        allocStorage(width, height);
+        break;
+    }
+
+    function allocStorage(width, height) {
+      gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA4, width, height);
+      wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no error after renderbufferStorage(internalformat = RGBA4).');
+    }
+
+    function attachBuffer(colorbuffer) {
+      gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, colorbuffer);
+    }
+
+    if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
+        testFailed('Framebuffer incomplete.');
+        return;
+    }
+
+    wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
+                        "user buffers have been initialized to 0");
+
+    gl.deleteFramebuffer(fbo);
+    gl.deleteRenderbuffer(colorbuffer);
+
+    // this clear should not matter we are about to resize
+    gl.clear(gl.COLOR_BUFFER_BIT);
+
+    gl.canvas.width += 1;
+    gl.canvas.height += 1;
+
+    debug('');
+}
+
+var successfullyParsed = true;
+</script>
+<script src="../../js/js-test-post.js"></script>
+</body>
+</html>