external/libvpx/libwebm: Update snapshot

Update libwebm snapshot. This update contains security fixes from upstream.

Upstream git hash: 229f49347d19b0ca0941e072b199a242ef6c5f2b

BUG=23167726

Change-Id: Id3e140e7b31ae11294724b1ecfe2e9c83b4d4207
(cherry picked from commit d0281a15b3c6bd91756e453cc9398c5ef412d99a)

void Cues::Init() const {
bool Cues::Init() const {
   if (m_cue_points)
    return true;
 
  if (m_count != 0 || m_preload_count != 0)
    return false;
 
   IMkvReader* const pReader = m_pSegment->m_pReader;
 
 const long long stop = m_start + m_size;
 long long pos = m_start;

 long cue_points_size = 0;

 while (pos < stop) {
 const long long idpos = pos;

 
     long len;
 
    const long long id = ReadID(pReader, pos, len);
    if (id < 0 || (pos + len) > stop) {
      return false;
    }
 
     pos += len;  // consume ID
 
     const long long size = ReadUInt(pReader, pos, len);
    if (size < 0 || (pos + len > stop)) {
      return false;
    }
 
     pos += len;  // consume Size field
    if (pos + size > stop) {
      return false;
    }
 
    if (id == 0x3B) {  // CuePoint ID
      if (!PreloadCuePoint(cue_points_size, idpos))
        return false;
    }
 
    pos += size;  // skip payload
   }
  return true;
 }

void Cues::Init() const {
   if (m_cue_points)
    return;
 
  assert(m_count == 0);
  assert(m_preload_count == 0);
 
   IMkvReader* const pReader = m_pSegment->m_pReader;
 
 const long long stop = m_start + m_size;
 long long pos = m_start;

 long cue_points_size = 0;

 while (pos < stop) {
 const long long idpos = pos;

 
     long len;
 
    const long long id = ReadUInt(pReader, pos, len);
    assert(id >= 0);  // TODO
    assert((pos + len) <= stop);
 
     pos += len;  // consume ID
 
     const long long size = ReadUInt(pReader, pos, len);
    assert(size >= 0);
    assert((pos + len) <= stop);
 
     pos += len;  // consume Size field
    assert((pos + size) <= stop);
 
    if (id == 0x3B)  // CuePoint ID
      PreloadCuePoint(cue_points_size, idpos);
 
    pos += size;  // consume payload
    assert(pos <= stop);
   }
 }
