Add support for encrypted WebM files as defined in the RFC.

media/webm/webm_content_encodings.h

 // Copyright (c) 2012 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_WEBM_WEBM_CONTENT_ENCODINGS_H_
 #define MEDIA_WEBM_WEBM_CONTENT_ENCODINGS_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
@@ skipping 24 matching lines @@
   enum EncryptionAlgo {
     kEncAlgoInvalid = -1,
     kEncAlgoNotEncrypted = 0,
     kEncAlgoDes = 1,
     kEncAlgo3des = 2,
     kEncAlgoTwofish = 3,
     kEncAlgoBlowfish = 4,
     kEncAlgoAes = 5,
   };
 
+  enum CipherMode {
+    kCipherModeInvalid = 0,
+    kCipherModeCtr = 1,
+  };
+
   ContentEncoding();
   ~ContentEncoding();
 
   int64 order() const { return order_; }
   void set_order(int64 order) { order_ = order; }
 
   Scope scope() const { return scope_; }
   void set_scope(Scope scope) { scope_ = scope; }
 
   Type type() const { return type_; }
   void set_type(Type type) { type_ = type; }
 
   EncryptionAlgo encryption_algo() const { return encryption_algo_; }
   void set_encryption_algo(EncryptionAlgo encryption_algo) {
     encryption_algo_ = encryption_algo;
   }
 
   const uint8* encryption_key_id() const { return encryption_key_id_.get(); }
   int encryption_key_id_size() const { return encryption_key_id_size_; }
 
   void SetEncryptionKeyId(const uint8* encryption_key_id, int size);
 
+  CipherMode cipher_mode() const { return cipher_mode_; }
+  void set_cipher_mode(CipherMode mode) { cipher_mode_ = mode; }
+
  private:
   int64 order_;
   Scope scope_;
   Type type_;
   EncryptionAlgo encryption_algo_;
   scoped_array<uint8> encryption_key_id_;
   int encryption_key_id_size_;
+  CipherMode cipher_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentEncoding);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_WEBM_WEBM_CONTENT_ENCODINGS_H_