--- a/dom/media/flac/FlacFrameParser.cpp
+++ b/dom/media/flac/FlacFrameParser.cpp
@@ -8,25 +8,25 @@
 #include "mp4_demuxer/ByteReader.h"
 #include "nsTArray.h"
 #include "OggCodecState.h"
 #include "VideoUtils.h"
 
 namespace mozilla
 {
 
-class AutoByteReader : public mp4_demuxer::ByteReader
+class MOZ_RAII AutoByteReader : public mp4_demuxer::ByteReader
 {
 public:
   AutoByteReader(const uint8_t* aData, size_t aSize)
     : mp4_demuxer::ByteReader(aData, aSize)
   {
 
   }
-  virtual ~AutoByteReader()
+  ~AutoByteReader()
   {
     DiscardRemaining();
   }
 };
 
 #define OGG_FLAC_METADATA_TYPE_STREAMINFO 0x7F
 #define FLAC_STREAMINFO_SIZE   34
 

--- a/dom/media/platforms/agnostic/WAVDecoder.cpp
+++ b/dom/media/platforms/agnostic/WAVDecoder.cpp
@@ -71,17 +71,17 @@ WaveDataDecoder::Input(MediaRawData* aSa
   }
   return NS_OK;
 }
 
 bool
 WaveDataDecoder::DoDecode(MediaRawData* aSample)
 {
   size_t aLength = aSample->Size();
-  ByteReader aReader = ByteReader(aSample->Data(), aLength);
+  ByteReader aReader(aSample->Data(), aLength);
   int64_t aOffset = aSample->mOffset;
   uint64_t aTstampUsecs = aSample->mTime;
 
   int32_t frames = aLength * 8 / mInfo.mBitDepth / mInfo.mChannels;
 
   AlignedAudioBuffer buffer(frames * mInfo.mChannels);
   if (!buffer) {
     return false;

--- a/dom/media/wave/WaveDemuxer.cpp
+++ b/dom/media/wave/WaveDemuxer.cpp
@@ -165,56 +165,55 @@ WAVTrackDemuxer::Init()
 
 bool
 WAVTrackDemuxer::RIFFParserInit()
 {
   RefPtr<MediaRawData> riffHeader = GetFileHeader(FindRIFFHeader());
   if (!riffHeader) {
     return false;
   }
-  ByteReader RIFFReader = ByteReader(riffHeader->Data(), 12);
+  ByteReader RIFFReader(riffHeader->Data(), 12);
   mRIFFParser.Parse(RIFFReader);
   return mRIFFParser.RiffHeader().IsValid(11);
 }
 
 bool
 WAVTrackDemuxer::HeaderParserInit()
 {
   RefPtr<MediaRawData> header = GetFileHeader(FindChunkHeader());
   if (!header) {
     return false;
   }
-  ByteReader HeaderReader = ByteReader(header->Data(), 8);
+  ByteReader HeaderReader(header->Data(), 8);
   mHeaderParser.Parse(HeaderReader);
   return true;
 }
 
 bool
 WAVTrackDemuxer::FmtChunkParserInit()
 {
   RefPtr<MediaRawData> fmtChunk = GetFileHeader(FindFmtChunk());
   if (!fmtChunk) {
     return false;
   }
-  ByteReader fmtReader = ByteReader(fmtChunk->Data(),
-                                    mHeaderParser.GiveHeader().ChunkSize());
+  ByteReader fmtReader(fmtChunk->Data(), mHeaderParser.GiveHeader().ChunkSize());
   mFmtParser.Parse(fmtReader);
   return true;
 }
 
 bool
 WAVTrackDemuxer::ListChunkParserInit(uint32_t aChunkSize)
 {
   uint32_t bytesRead = 0;
 
   RefPtr<MediaRawData> infoTag = GetFileHeader(FindInfoTag());
   if (!infoTag) {
     return false;
   }
-  ByteReader infoTagReader = ByteReader(infoTag->Data(), 4);
+  ByteReader infoTagReader(infoTag->Data(), 4);
   if (!infoTagReader.CanRead32() || infoTagReader.ReadU32() != INFO_CODE) {
     return false;
   }
 
   bytesRead += 4;
 
   while (bytesRead < aChunkSize) {
     if (!HeaderParserInit()) {

--- a/media/libstagefright/binding/include/mp4_demuxer/ByteReader.h
+++ b/media/libstagefright/binding/include/mp4_demuxer/ByteReader.h
@@ -7,17 +7,17 @@
 
 #include "mozilla/EndianUtils.h"
 #include "mozilla/Vector.h"
 #include "nsTArray.h"
 #include "MediaData.h"
 
 namespace mp4_demuxer {
 
-class ByteReader
+class MOZ_RAII ByteReader
 {
 public:
   ByteReader() : mPtr(nullptr), mRemaining(0) {}
   explicit ByteReader(const mozilla::Vector<uint8_t>& aData)
     : mPtr(aData.begin()), mRemaining(aData.length()), mLength(aData.length())
   {
   }
   ByteReader(const uint8_t* aData, size_t aSize)