Fix WebViewClient form submission CTS failure

Since we picked up webkit r65340, we cannot trigger a page navigation
in the onload handler and expect it to create a history entry. We must
do the navigation asynchronously.

Requires a change in external/webkit, see
I592ae7ba0acc7478789599aeb6973675ed415a37

Bug: 3241908

Change-Id: I8cefff3aeb0e05c63b4b7900777096abe2937841
diff --git a/tests/assets/webkit/jsform.html b/tests/assets/webkit/jsform.html
index ddf01f8..1781194 100644
--- a/tests/assets/webkit/jsform.html
+++ b/tests/assets/webkit/jsform.html
@@ -24,7 +24,7 @@
             }
         }
     </script>
-    <body onload="fireSubmit()">
+    <body onload="window.setTimeout(function() { fireSubmit(); }, 0);">
         javascript form test
         <form id="formId" action="test.html#result" method="post">
             <input type="hidden" name="foo" value="bar" />