Support for parsing encrypted WebM streams by src.

media/crypto/decryptor_helpers.cc

Index: media/crypto/decryptor_helpers.cc
diff --git a/media/crypto/decryptor_helpers.cc b/media/crypto/decryptor_helpers.cc
new file mode 100644
index 0000000000000000000000000000000000000000..58154bf3528fe11c47245e6321570f2df9feabba
--- /dev/null
+++ b/media/crypto/decryptor_helpers.cc
@@ -0,0 +1,17 @@
+// 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.
+
+#include "media/crypto/decryptor_helpers.h"
+
+#include "media/base/decrypt_config.h"
+
+namespace media {
+
+std::string GenerateCounterBlock(uint64 iv) {
+  std::string counter_block(reinterpret_cast<char*>(&iv), sizeof(iv));

[ddorwin, 2012/09/01 16:46:41]

I wonder if we'd be better off reserving the final size (kDecryptionKeySize) and
copying in.

+  counter_block.append(DecryptConfig::kDecryptionKeySize - sizeof(iv), 0);
+  return counter_block;
+}
+
+}  // media

[xhwang, 2012/08/29 05:08:14]

// namespace media