Improve usefulness of webglcontextcreationerror statusMessage

third_party/WebKit/LayoutTests/fast/canvas/webgl/webgl-error-response.html

 <!-- This is a test for crbug.com/412440, tests meaningful information in
 WebGL context creation error message. -->
 <script src="../../../resources/js-test.js"></script>
 <canvas id="webgl-canvas" width="200" height="200" class="nomargin"></canvas>
 <script>
 function main()
 {
   if (!window.testRunner) {
     testFailed("Requires window.testRunner");
   } else {
     initTest();
   }
 }
 
 function initTest() {
   var canvas = document.getElementById("webgl-canvas");
   testRunner.forceNextWebGLContextCreationToFail();
   canvas.addEventListener("webglcontextcreationerror", onContextCreationError, false);
   var gl = canvas.getContext("webgl");
   testRunner.dumpAsText();
 }
 
 function onContextCreationError(e) {
   var splitStatus = e.statusMessage.split(",");
-  var stringLocator = 1;
-  var status = true;
-  // Start iterating from 1 as , the initial message has no data.
+  var error =  "";
   for (var i = 1; i < splitStatus.length; i++) {
     var gpuInfoStr = splitStatus[i].split(" = ");
-    if (gpuInfoStr[stringLocator] == "")
-      status = false;
+    var key = gpuInfoStr[0].trim();
+    var value = gpuInfoStr[1];
+    if (key == "DEVICE" && (value == "0x0000" || value == ""))
+      error = error + "DeviceID is null.";
+    if (key == "VENDOR" && (value == "0x0000" || value == ""))
+      error = error + "VendorID is null.";
+    if ((key == "GL_VENDOR" ||
+      key == "GL_RENDERER" ||
+      key == "GL_VERSION" ||
+      key == "Sandboxed" ||
+      key == "Optimus" ||
+      key == "AMD switchable" ||
+      key == "Reset notification strategy" ||
+      key == "GPU process crash count" ||
+      key == "ErrorMessage") && (value == "")) {
+        error = error + "Gpu data is incorrect.";

[Zhenyao Mo, 2015/10/16 18:46:12]

We may not always have GL strings because we only collect them on GPU process
startup, and then send such info back to browser, and then to renderer.  So it's
likely the renderer process already starts creating a WebGL context and failed.

[sivag, 2015/10/19 16:19:23]

Done.

+      }

[Zhenyao Mo, 2015/10/16 18:46:12]

nit: indentation wrong.

[sivag, 2015/10/19 16:19:23]

Done.

   }
-  if(status)
+  if (error.length)
+    testFailed("webglcontextcreationerror test failed" + error);
+  else
     testPassed("Status message displayed for webglcontextcreationerror");
-  else
-    testFailed("Context creation error test failed");
+
 }
 main();
 </script>