Add 'error' parameter to 'window.onerror' handlers.

LayoutTests/fast/events/window-onerror-01-expected.txt

Index: LayoutTests/fast/events/window-onerror-01-expected.txt
diff --git a/LayoutTests/fast/events/window-onerror-01-expected.txt b/LayoutTests/fast/events/window-onerror-01-expected.txt
index ee2d550963406e8622313cfcf5dbe1f5f9271010..131f00ddd04aac03a0b75558682d8d8901be33d2 100644
--- a/LayoutTests/fast/events/window-onerror-01-expected.txt
+++ b/LayoutTests/fast/events/window-onerror-01-expected.txt
@@ -4,6 +4,12 @@ On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE
 
 
 window.onerror: "Uncaught ReferenceError: hahaha_good_luck_finding_me is not defined" at window-onerror-01.html (Line: 14, Column: 8)
+ReferenceError: hahaha_good_luck_finding_me is not defined
+    at file:///Volumes/Repositories/blink/src/third_party/WebKit/LayoutTests/fast/events/window-onerror-01.html:14:9
+
+ReferenceError: hahaha_good_luck_finding_me is not defined
+    at window-onerror-01.html:14:9
+
 Returning 'true': the error should not be reported in the console as an unhandled exception.
 PASS successfullyParsed is true