Cast: Adding helper crypto classes

media/cast/utility/cast_decryption_handler.h

Index: media/cast/utility/cast_decryption_handler.h
diff --git a/media/cast/utility/cast_decryption_handler.h b/media/cast/utility/cast_decryption_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..c0e344afc98814eea74d50edbab3075d65ca4c19
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+++ b/media/cast/utility/cast_decryption_handler.h
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+// 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 MEDIA_CAST_UTILITY_CAST_DECRYPTION_HANDLER_H_
+#define MEDIA_CAST_UTILITY_CAST_DECRYPTION_HANDLER_H_
+
+// Helper class to handle decryption for the Cast library.
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_piece.h"
+#include "base/threading/non_thread_safe.h"
+
+namespace crypto {
+class Encryptor;
+class SymmetricKey;
+}
+
+namespace media {
+namespace cast {
+
+class CastDecryptionHandler : public base::NonThreadSafe {
+ public:
+  CastDecryptionHandler();
+  ~CastDecryptionHandler();
+
+  bool Initialize(std::string aes_key, std::string aes_iv_mask);
+
+  bool Decrypt(uint32 frame_id,
+               const base::StringPiece& ciphertext,
+               std::string* plaintext);
+
+  bool initialized() const { return initialized_; }
+
+ private:
+  scoped_ptr<crypto::SymmetricKey> key_;
+  std::string iv_mask_;
+  scoped_ptr<crypto::Encryptor> decryptor_;
+  bool initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastDecryptionHandler);
+};
+
+}  // namespace cast
+}  // namespace media
+
+#endif  // MEDIA_CAST_UTILITY_CAST_DECRYPTION_HANDLER_H_