Credential Management: Add 'Credential::type' attribute.

Source/platform/credentialmanager/PlatformFederatedCredential.cpp

 // 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.
 
 #include "config.h"
 #include "platform/credentialmanager/PlatformFederatedCredential.h"
 
 namespace blink {
 
 PlatformFederatedCredential* PlatformFederatedCredential::create(const String& id, const KURL& provider, const String& name, const KURL& iconURL)
 {
     return new PlatformFederatedCredential(id, provider, name, iconURL);
 }
 
 PlatformFederatedCredential::PlatformFederatedCredential(const String& id, const KURL& provider, const String& name, const KURL& iconURL)
     : PlatformCredential(id, name, iconURL)
     , m_provider(provider)
 {
+    setType("federated");
 }
 
 PlatformFederatedCredential::~PlatformFederatedCredential()
 {
 }
 
 } // namespace blink