Add additional test harness error handling to test_controller.

pkg/unittest/test_controller.js

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Test controller logic - used by unit test harness to embed tests in
  * DumpRenderTree.
  */
 
+// Clear the console before every test run.
+if (typeof console == "object" && typeof console.clear == "function") {
+  console.clear();

[ahe, 2012/10/30 09:48:51]

Unfortunately, I only think this works in Firebug. But it is worth a try.

+}
+
+// Set window onerror to make sure that we catch test harness errors across all
+// browsers.
+window.onerror = function (message, url, lineNumber) {
+  showErrorAndExit("\n\n" + url + ":" + lineNumber + ":\n" + message + "\n\n");
+  window.postMessage('unittest-suite-external-error', '*');
+};
+
 if (navigator.webkitStartDart) {
   navigator.webkitStartDart();
 }
 
 // testRunner is provided by DRT or WebKit's layout tests.
 // It is not available in selenium tests.
 var testRunner = window.testRunner || window.layoutTestController;
 
 var waitForDone = false;
 
@@ skipping 92 matching lines @@
 function dartMainRunner(main) {
   window.postMessage('dart-calling-main', '*');
   try {
     main();
   } catch (e) {
     window.postMessage('unittest-suite-fail', '*');
     return;
   }
   window.postMessage('dart-main-done', '*');
 }