Support for parsing encrypted WebM streams by src.

media/webm/webm_cluster_parser.cc

Index: media/webm/webm_cluster_parser.cc
diff --git a/media/webm/webm_cluster_parser.cc b/media/webm/webm_cluster_parser.cc
index cb7501e23d2acef634ab3987961e5f183a5aba01..70356b8965882744503574113fb7a45e14b61196 100644
--- a/media/webm/webm_cluster_parser.cc
+++ b/media/webm/webm_cluster_parser.cc
@@ -10,19 +10,11 @@
 #include "base/sys_byteorder.h"
 #include "media/base/data_buffer.h"
 #include "media/base/decrypt_config.h"
+#include "media/crypto/decryptor_helpers.h"
 #include "media/webm/webm_constants.h"
 
 namespace media {
 
-// Generates a 16 byte CTR counter block. The CTR counter block format is a
-// CTR IV appended with a CTR block counter. |iv| is an 8 byte CTR IV.
-// Returns a string of kDecryptionKeySize bytes.
-static std::string GenerateCounterBlock(uint64 iv) {
-  std::string counter_block(reinterpret_cast<char*>(&iv), sizeof(iv));
-  counter_block.append(DecryptConfig::kDecryptionKeySize - sizeof(iv), 0);
-  return counter_block;
-}
-
 WebMClusterParser::WebMClusterParser(int64 timecode_scale,
                                      int audio_track_num,
                                      int video_track_num,