Fix race condition in GpuProcess_skip_gpu_process.

content/test/data/gpu/functional_files/context.js

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Global variable.
+// Global variables.
 var gl_context;
+var gl_renderer;
 
 initializeWebGL = function(canvas) {
   gl_context = null;
   // Try to grab the standard context.
   gl_context = canvas.getContext("webgl") ||
                canvas.getContext("experimental-webgl");
   // If we don't have a GL context, give up now.
   if (!gl_context) {
     err = "Unable to initialize WebGL. Your browser may not support it.";
-    if (domAutomationController) {
+    if (window.domAutomationController) {
       console.log(err);
     } else {
       alert(err);
     }
   }
 }
 
 startWebGLContext = function() {
   var canvas = document.getElementById("glcanvas");
   // Initialize the GL context.
   initializeWebGL(canvas);
 
   // Only continue if WebGL is available and working.
   if (gl_context) {
     gl_context.clearColor(0.0, 0.0, 0.0, 1.0);
     gl_context.enable(gl_context.DEPTH_TEST);
     gl_context.depthFunc(gl_context.LEQUAL);
     gl_context.clearDepth(1);
     gl_context.clear(gl_context.COLOR_BUFFER_BIT |
                      gl_context.DEPTH_BUFFER_BIT);
+
+    // Also fetch the unmasked GL_RENDERER string.
+    var ext = gl_context.getExtension("WEBGL_debug_renderer_info");
+    gl_renderer = gl_context.getParameter(ext.UNMASKED_RENDERER_WEBGL);
   }
 
-  domAutomationController.setAutomationId(0);
-  domAutomationController.send("FINISHED");
+  if (window.domAutomationController) {
+    domAutomationController.setAutomationId(0);
+    domAutomationController.send("FINISHED");
+  }
 }