Support for parsing encrypted WebM streams by src.

media/webm/webm_crypto_helpers.h

+// Copyright (c) 2013 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_CRYPTO_HELPERS_H_
+#define MEDIA_WEBM_WEBM_CRYPTO_HELPERS_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/decoder_buffer.h"
+
+namespace media {
+
+// TODO(xhwang): Figure out the init data type appropriately once it's spec'ed.
+// See https://www.w3.org/Bugs/Public/show_bug.cgi?id=19096 for more
+// information.
+const char kWebMEncryptInitDataType[] = "video/webm";
+
+// Returns an initialized DecryptConfig, which can be sent to the Decryptor if
+// the stream has potentially encrypted frames. Every encrypted Block has a
+// signal byte, and if the frame is encrypted an IV, prepended to the frame.
+// Leaving the initialization vector empty will tell the decryptor that the
+// frame is unencrypted. Current encrypted WebM request for comments
+// specification is here
+// http://wiki.webmproject.org/encryption/webm-encryption-rfc
+scoped_ptr<DecryptConfig> WebMCreateDecryptConfig(
+    const uint8* data, int data_size,
+    const uint8* key_id, int key_id_size);
+
+}  // namespace media
+
+#endif  // MEDIA_WEBM_WEBM_CRYPT_HELPERS_H_