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diff --git a/dom/canvas/test/webgl-conf/checkout/conformance/context/context-no-alpha-fbo-with-alpha.html b/dom/canvas/test/webgl-conf/checkout/conformance/context/context-no-alpha-fbo-with-alpha.html
new file mode 100644
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--- /dev/null
+++ b/dom/canvas/test/webgl-conf/checkout/conformance/context/context-no-alpha-fbo-with-alpha.html
@@ -0,0 +1,77 @@
+<!--
+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>
+
+<script>
+"use strict";
+
+var wtu = WebGLTestUtils;
+
+// This declaration needs to be global for "shouldBe" to see it
+var gl;
+
+function init()
+{
+    description('Verify that a WebGL context with alpha:false still works correctly after handling textures with an alpha channel.');
+
+    runTest();
+}
+
+function getWebGL(contextAttribs)
+{
+    return wtu.create3DContext("c", contextAttribs);
+}
+
+function runTest()
+{
+    var buf = new Uint8Array(1 * 1 * 4);
+    shouldBeNonNull("gl = getWebGL({ alpha: false, antialias: false })");
+
+    // Clear to black. Alpha channel of clearColor() is ignored.
+    gl.clearColor(0.0, 0.0, 0.0, 0.7);
+    gl.clear(gl.COLOR_BUFFER_BIT);
+    wtu.checkCanvasRect(gl, 0, 0, 1, 1, [0, 0, 0, 255],
+                        "Alpha channel of clearColor should be ignored");
+
+    wtu.waitForComposite(function() {
+        // Make a new framebuffer and attach a texture with an alpha channel.
+        var fbo = gl.createFramebuffer();
+        gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
+        var texture = gl.createTexture();
+        gl.bindTexture(gl.TEXTURE_2D, texture);
+        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
+        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
+
+        // Clear texture. Note that alpha channel is not 1.0.
+        gl.clearColor(1.0, 0.0, 0.0, 0.5);
+        gl.clear(gl.COLOR_BUFFER_BIT);
+        wtu.checkCanvasRect(gl, 0, 0, 1, 1, [255, 0, 0, 128],
+                            "Alpha channel of clearColor should be obeyed for FBO with alpha channel",
+                            1);
+
+        // Bind back buffer and check that its alpha channel is still 1.0.
+        gl.bindFramebuffer(gl.FRAMEBUFFER, null);
+        wtu.checkCanvasRect(gl, 0, 0, 1, 1, [0, 0, 0, 255],
+                            "Alpha channel of back buffer should still be 255");
+        finishTest();
+    });
+}
+
+</script>
+</head>
+<body onload="init()">
+<div id="description"></div>
+<div id="console"></div>
+<canvas width="20" height="20" style="border: 1px solid blue;" id="c"></canvas>
+</body>
+</html>