Add support for codepen to form_based_credentials_background

tools/telemetry/telemetry/core/backends/codepen_credentials_backend_unittest.py

Index: tools/telemetry/telemetry/core/backends/codepen_credentials_backend_unittest.py
diff --git a/tools/telemetry/telemetry/core/backends/codepen_credentials_backend_unittest.py b/tools/telemetry/telemetry/core/backends/codepen_credentials_backend_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..2142429f220e49ed04f3a9bc7c8fce5dbd50b6a1
--- /dev/null
+++ b/tools/telemetry/telemetry/core/backends/codepen_credentials_backend_unittest.py
@@ -0,0 +1,18 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+from telemetry.core.backends import form_based_credentials_backend_unittest_base
+from telemetry.core.backends import codepen_credentials_backend
+
+
+class TestCodePenCredentialsBackend(
+    form_based_credentials_backend_unittest_base.
+    FormBasedCredentialsBackendUnitTestBase):
+  def setUp(self):
+    self._credentials_type = 'codepen'
+
+  def testLoginUsingMock(self):
+    self._LoginUsingMock(
+        codepen_credentials_backend.CodePenCredentialsBackend(),
+        'https://codepen.io/login', 'login-email-field', 'login-password',
+        'login-login-form', 'document.querySelector(".login-area") === null')