CREDENTIAL: Do type checks for credential constructors.

third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html

Index: third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html b/third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html
index 62d7a3df811210ab71b30e4e21530764567c586f..eced29d615a7555f72d5ff6856e0246dd208d853 100644
--- a/third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html
+++ b/third_party/WebKit/LayoutTests/http/tests/credentialmanager/passwordcredential-basics.html
@@ -87,4 +87,25 @@ test(function() {
     credential.additionalData = additionalData;
     assert_equals(credential.additionalData, additionalData);
 }, 'Verify the basics of "idName", "passwordName", and "additionalData"');
+
+test(function() {
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential(); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({}); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'id': undefined }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'id': '' }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'password': undefined }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'password': '' }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'id': undefined, 'password': undefined }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'id': undefined, 'password': '' }); });
+    assert_throws(new TypeError(),
+                  () => { new PasswordCredential({ 'id': undefined, 'password': undefined }); });
+}, 'PasswordCredential objects require IDs and Passwords');
 </script>