Fix AnnexB validation logic to work with encrypted content.

media/formats/mp4/mp4_stream_parser.cc

Index: media/formats/mp4/mp4_stream_parser.cc
diff --git a/media/formats/mp4/mp4_stream_parser.cc b/media/formats/mp4/mp4_stream_parser.cc
index 0eb15d9f2ce09c64f5f332438c46c136f2c554ed..4c8d6574518adaebb82d7e734c2fdfbb95641511 100644
--- a/media/formats/mp4/mp4_stream_parser.cc
+++ b/media/formats/mp4/mp4_stream_parser.cc
@@ -382,8 +382,7 @@ bool MP4StreamParser::PrepareAVCBuffer(
     RCHECK(AVC::InsertParamSetsAnnexB(avc_config, frame_buf, subsamples));
   }
 
-  // TODO(acolwell): Improve IsValidAnnexB() so it can handle encrypted content.
-  DCHECK(runs_->is_encrypted() || AVC::IsValidAnnexB(*frame_buf));
+  DCHECK(AVC::IsValidAnnexB(*frame_buf, *subsamples));
   return true;
 }