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

media/crypto/aes_decryptor.cc

Index: media/crypto/aes_decryptor.cc
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index cbb75b37bd33457f74b9f540d652ae01bbd77c19..7b8feca73ebae36b6ec6f4f5186718d773643f99 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -14,40 +14,6 @@
 
 namespace media {
 
-// TODO(xhwang): Get real IV from frames.
-static const char kInitialCounter[] = "0000000000000000";
-
-// Decrypt |input| using |key|.
-// Return a DecoderBuffer with the decrypted data if decryption succeeded.
-// Return NULL if decryption failed.
-static scoped_refptr<DecoderBuffer> DecryptData(const DecoderBuffer& input,
-                                                crypto::SymmetricKey* key) {
-  CHECK(input.GetDataSize());
-  CHECK(key);
-
-  // Initialize encryption data.
-  // The IV must be exactly as long as the cipher block size.
-  crypto::Encryptor encryptor;
-  if (!encryptor.Init(key, crypto::Encryptor::CBC, kInitialCounter)) {
-    DVLOG(1) << "Could not initialize encryptor.";
-    return NULL;
-  }
-
-  std::string decrypted_text;
-  base::StringPiece encrypted_text(
-      reinterpret_cast<const char*>(input.GetData()),
-      input.GetDataSize());
-  if (!encryptor.Decrypt(encrypted_text, &decrypted_text)) {
-    DVLOG(1) << "Could not decrypt data.";
-    return NULL;
-  }
-
-  // TODO(xhwang): Find a way to avoid this data copy.
-  return DecoderBuffer::CopyFrom(
-      reinterpret_cast<const uint8*>(decrypted_text.data()),
-      decrypted_text.size());
-}
-
 AesDecryptor::AesDecryptor() {}
 
 AesDecryptor::~AesDecryptor() {
@@ -99,7 +65,8 @@ scoped_refptr<DecoderBuffer> AesDecryptor::Decrypt(
     key = found->second;
   }
 
-  scoped_refptr<DecoderBuffer> decrypted = DecryptData(*encrypted, key);
+  scoped_refptr<DecoderBuffer> decrypted =
+      Decryptor::DecryptData(*encrypted, key, 0);
 
   if (decrypted) {
     decrypted->SetTimestamp(encrypted->GetTimestamp());