Credential manager: Convert strings to URLs early.

LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html

Index: LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html
diff --git a/LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html b/LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html
index 1814a4622266079cd62f195374a2d2345494332d..f3470cb93002407bc05d4498adf6a9e0e858f55d 100644
--- a/LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html
+++ b/LayoutTests/http/tests/credentialmanager/federatedcredential-basics.html
@@ -22,4 +22,22 @@ test(function() {
     assert_equals(credential.avatarURL, 'https://example.com/avatar.png');
     assert_equals(credential.federation, 'https://federation.net/');
 }, 'Interfaces and attributes of FederatedCredential');
+
+test(function() {
+    try {
+        var credential = new FederatedCredential('id', 'name', '-', 'https://federation.net/');

[philipj_slow, 2014/08/12 09:42:40]

It looks like assert_throws would simplify this to assert_throws(new
SyntaxError(), function() { new FederatedCredential('id', 'name', '-',
'https://federation.net/'); });

+        assert_unreached("Creating a credential with an invalid URL should throw a SyntaxError.");
+    } catch (e) {
+        assert_equals(e.name, "SyntaxError");
+    }
+}, 'Invalid avatar URL throws.');

[philipj_slow, 2014/08/12 09:42:40]

In web-platform-tests I've been advised to not put the pass condition in the
test name, but rather just say what the test does. I think it's good advice, but
it's a matter of style so take your pick :)

+
+test(function() {
+    try {
+        var credential = new FederatedCredential('id', 'name', 'https://example.com/avatar.png', '-');
+        assert_unreached("Creating a credential with an invalid URL should throw a SyntaxError.");
+    } catch (e) {
+        assert_equals(e.name, "SyntaxError");
+    }
+}, 'Invalid federation URL throws.');
 </script>