HTMLPreloadScanner should only use valid <base> urls

LayoutTests/fast/parser/badurl-base-should-be-ignored.html

Index: LayoutTests/fast/parser/badurl-base-should-be-ignored.html
diff --git a/LayoutTests/fast/parser/badurl-base-should-be-ignored.html b/LayoutTests/fast/parser/badurl-base-should-be-ignored.html
new file mode 100644
index 0000000000000000000000000000000000000000..a9a589cab4733d52e21cda1d615bf5b89f132d41
--- /dev/null
+++ b/LayoutTests/fast/parser/badurl-base-should-be-ignored.html
@@ -0,0 +1,10 @@
+<script src="../../resources/js-test.js"></script>

[Yoav Weiss, 2015/04/02 05:29:09]

Can you add a DOCTYPE?

[kouhei (in TOK), 2015/04/02 06:19:39]

Done.

+<base href="gopher:???:"></base>
+<script>
+window.fail = false;
+</script>
+<!-- The resource should not be read, as the baseUrl is now set to empty from reading invalid url -->
+<script src="resources/fail.js"></script>

[Yoav Weiss, 2015/04/02 05:29:09]

Did that fail before your change?
AFAIU you're just testing if the JS was applied, not if the preloadScanner
picked it up and downloaded it.

[kouhei (in TOK), 2015/04/02 06:19:39]

No.
Yes. Currently we can't test the preloader reliably.

+<script>
+shouldBeFalse('window.fail')
+</script>