document.lastModified should consider user's local time zone

LayoutTests/http/tests/misc/last-modified-parsing.html

Index: LayoutTests/http/tests/misc/last-modified-parsing.html
diff --git a/LayoutTests/http/tests/misc/last-modified-parsing.html b/LayoutTests/http/tests/misc/last-modified-parsing.html
index e9bd793450755ab0bc5b8812d1c5b9e38d3d020d..9200b9b465cf8d536f0ff4ea01db692936b047c0 100644
--- a/LayoutTests/http/tests/misc/last-modified-parsing.html
+++ b/LayoutTests/http/tests/misc/last-modified-parsing.html
@@ -4,8 +4,20 @@ if (window.testRunner) {
     testRunner.dumpChildFramesAsText();
 }
 
+function getExpectedLastModified(lastModified) {
+    var date = new Date(lastModified);
+    var month = ("0" + (date.getMonth() + 1)).slice(-2);

[tkent, 2014/07/28 00:40:26]

nit: quotation mark is inconsistent.  Other lines in in this test uses
single-quote, and this line uses double-quote.

[kangil_, 2014/07/31 00:45:45]

Done.

+    var day = ("0" + date.getDate()).slice(-2);
+    var hour = ("0" + date.getHours()).slice(-2);
+    var minute = ("0" + date.getMinutes()).slice(-2);
+    var second = ("0" + date.getSeconds()).slice(-2);
+    var result = month + '/' + day + '/' + date.getFullYear() + ' ' + hour + ':' + minute + ':' + second;
+    return result;
+}
+
 function test(text) {
-    document.write('<iframe src="../resources/last-modified.php?date=' + escape(text) + '"></iframe>');
+    var url = '../resources/last-modified.php?date=' + escape(text) + '&expected=' + escape(getExpectedLastModified(text));
+    document.write('<iframe id="test" src="' + url + '"></iframe>');
 }
 
 test('Mon, 21 Nov 2008 01:03:33 GMT');