--- a/dom/media/ogg/OggCodecState.h
+++ b/dom/media/ogg/OggCodecState.h
@@ -246,30 +246,30 @@ protected:
                         uint32_t aLength);
 };
 
 class VorbisState : public OggCodecState {
 public:
   explicit VorbisState(ogg_page* aBosPage);
   virtual ~VorbisState();
 
-  CodecType GetType() { return TYPE_VORBIS; }
-  bool DecodeHeader(ogg_packet* aPacket);
-  int64_t Time(int64_t granulepos);
-  int64_t PacketDuration(ogg_packet* aPacket);
-  bool Init();
-  nsresult Reset();
-  bool IsHeader(ogg_packet* aPacket);
-  nsresult PageIn(ogg_page* aPage); 
+  CodecType GetType() override { return TYPE_VORBIS; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  nsresult Reset() override;
+  bool IsHeader(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
 
   // Return a hash table with tag metadata.
-  MetadataTags* GetTags();
+  MetadataTags* GetTags() override;
 
   // Returns the end time that a granulepos represents.
-  static int64_t Time(vorbis_info* aInfo, int64_t aGranulePos); 
+  static int64_t Time(vorbis_info* aInfo, int64_t aGranulePos);
 
   vorbis_info mInfo;
   vorbis_comment mComment;
   vorbis_dsp_state mDsp;
   vorbis_block mBlock;
 
 private:
 
@@ -320,25 +320,25 @@ int TheoraVersion(th_info* info,
                   unsigned char min,
                   unsigned char sub);
 
 class TheoraState : public OggCodecState {
 public:
   explicit TheoraState(ogg_page* aBosPage);
   virtual ~TheoraState();
 
-  CodecType GetType() { return TYPE_THEORA; }
-  bool DecodeHeader(ogg_packet* aPacket);
-  int64_t Time(int64_t granulepos);
-  int64_t StartTime(int64_t granulepos);
-  int64_t PacketDuration(ogg_packet* aPacket);
-  bool Init();
-  bool IsHeader(ogg_packet* aPacket);
-  bool IsKeyframe(ogg_packet* aPacket);
-  nsresult PageIn(ogg_page* aPage); 
+  CodecType GetType() override { return TYPE_THEORA; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override;
+  int64_t StartTime(int64_t granulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  bool IsHeader(ogg_packet* aPacket) override;
+  bool IsKeyframe(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
 
   // Returns the maximum number of microseconds which a keyframe can be offset
   // from any given interframe.
   int64_t MaxKeyframeOffset();
 
   // Returns the end time that a granulepos represents.
   static int64_t Time(th_info* aInfo, int64_t aGranulePos); 
 
@@ -360,25 +360,25 @@ private:
 
 };
 
 class OpusState : public OggCodecState {
 public:
   explicit OpusState(ogg_page* aBosPage);
   virtual ~OpusState();
 
-  CodecType GetType() { return TYPE_OPUS; }
-  bool DecodeHeader(ogg_packet* aPacket);
-  int64_t Time(int64_t aGranulepos);
-  int64_t PacketDuration(ogg_packet* aPacket);
-  bool Init();
-  nsresult Reset();
+  CodecType GetType() override { return TYPE_OPUS; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t aGranulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  nsresult Reset() override;
   nsresult Reset(bool aStart);
-  bool IsHeader(ogg_packet* aPacket);
-  nsresult PageIn(ogg_page* aPage);
+  bool IsHeader(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
 
   // Returns the end time that a granulepos represents.
   static int64_t Time(int aPreSkip, int64_t aGranulepos);
 
   // Various fields from the Ogg Opus header.
   int mRate;        // Sample rate the decoder uses (always 48 kHz).
   int mChannels;    // Number of channels the stream encodes.
   uint16_t mPreSkip; // Number of samples to strip after decoder reset.
@@ -392,17 +392,17 @@ public:
   OpusMSDecoder* mDecoder;
 
   int mSkip;        // Number of samples left to trim before playback.
   // Granule position (end sample) of the last decoded Opus packet. This is
   // used to calculate the amount we should trim from the last packet.
   int64_t mPrevPacketGranulepos;
 
   // Construct and return a table of tags from the metadata header.
-  MetadataTags* GetTags();
+  MetadataTags* GetTags() override;
 
 private:
 
   // Reconstructs the granulepos of Opus packets stored in the
   // mUnstamped array. mUnstamped must be filled with consecutive packets from
   // the stream, with the last packet having a known granulepos. Using this
   // known granulepos, and the known frame numbers, we recover the granulepos
   // of all frames in the array. This enables us to determine their timestamps.
@@ -443,21 +443,21 @@ typedef struct {
 
 class SkeletonState : public OggCodecState {
 public:
   explicit SkeletonState(ogg_page* aBosPage);
   ~SkeletonState();
 
   nsClassHashtable<nsUint32HashKey, MessageField> mMsgFieldStore;
 
-  CodecType GetType() { return TYPE_SKELETON; }
-  bool DecodeHeader(ogg_packet* aPacket);
-  int64_t Time(int64_t granulepos) { return -1; }
-  bool Init() { return true; }
-  bool IsHeader(ogg_packet* aPacket) { return true; }
+  CodecType GetType() override { return TYPE_SKELETON; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override { return -1; }
+  bool Init() override { return true; }
+  bool IsHeader(ogg_packet* aPacket) override { return true; }
 
   // Return true if the given time (in milliseconds) is within
   // the presentation time defined in the skeleton track.
   bool IsPresentable(int64_t aTime) { return aTime >= mPresentationTime; }
 
   // Stores the offset of the page on which a keyframe starts,
   // and its presentation time.
   class nsKeyPoint {