Make the default testharness.js timeout longer than the LayoutTests timeout

LayoutTests/resources/testharness.js

 /*
 Distributed under both the W3C Test Suite License [1] and the W3C
 3-clause BSD License [2]. To contribute to a W3C Test Suite, see the
 policies and contribution forms [3].
 
 [1] http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
 [2] http://www.w3.org/Consortium/Legal/2008/03-bsd-license
 [3] http://www.w3.org/2004/10/27-testcases
 */
 
@@ skipping 337 matching lines @@
  *   asserts that object has an own property property_name
  *
  * assert_not_exists(object, property_name, description)
  *   *** deprecated ***
  *   assert that object does not have own property property_name
  */
 
 (function ()
 {
     var debug = false;
-    // default timeout is 5 seconds, test can override if needed
+    // default timeout is 5 minutes, to let LayoutTests timeout first
     var settings = {
       output:true,
-      timeout:5000,
-      test_timeout:2000
+      timeout:300000,
+      test_timeout:300000
     };
 
     var xhtml_ns = "http://www.w3.org/1999/xhtml";
 
     // script_prefix is used by Output.prototype.show_results() to figure out
     // where to get testharness.css from.  It's enclosed in an extra closure to
     // not pollute the library's namespace with variables like "src".
     var script_prefix = null;
     (function ()
     {
@@ skipping 1851 matching lines @@
         }
         catch(e) {
             // This is the case where postMessage isn't supported AND accessing a
             // window property across origins throws (e.g. old Firefox browser).
             supports = false;
         }
         return supports;
     }
 })();
 // vim: set expandtab shiftwidth=4 tabstop=4: