Credential Manager: Add platform-exposed Credential objects.

Source/platform/credentialmanager/PlatformFederatedCredential.h

+// 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.
+
+#ifndef PlatformFederatedCredential_h
+#define PlatformFederatedCredential_h
+
+#include "platform/credentialmanager/PlatformCredential.h"
+#include "platform/heap/Handle.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+class PLATFORM_EXPORT PlatformFederatedCredential FINAL : public PlatformCredential {
+    WTF_MAKE_NONCOPYABLE(PlatformFederatedCredential);
+public:
+    static PlatformFederatedCredential* create(const String& id, const String& name, const String& avatarURL, const String& federation);
+    virtual ~PlatformFederatedCredential();
+
+    const String& federation() const { return m_federation; }
+
+private:
+    PlatformFederatedCredential(const String& id, const String& name, const String& avatarURL, const String& federation);
+
+    String m_federation;
+};
+
+} // namespace blink
+
+#endif // PlatformFederatedCredential_h