--- a/dom/media/webaudio/AnalyserNode.cpp
+++ b/dom/media/webaudio/AnalyserNode.cpp
@@ -11,19 +11,19 @@
 #include "mozilla/Mutex.h"
 #include "mozilla/PodOperations.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_ISUPPORTS_INHERITED0(AnalyserNode, AudioNode)
 
-class AnalyserNodeEngine : public AudioNodeEngine
+class AnalyserNodeEngine final : public AudioNodeEngine
 {
-  class TransferBuffer : public nsRunnable
+  class TransferBuffer final : public nsRunnable
   {
   public:
     TransferBuffer(AudioNodeStream* aStream,
                    const AudioChunk& aChunk)
       : mStream(aStream)
       , mChunk(aChunk)
     {
     }

--- a/dom/media/webaudio/AnalyserNode.h
+++ b/dom/media/webaudio/AnalyserNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "FFTBlock.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class AnalyserNode : public AudioNode
+class AnalyserNode final : public AudioNode
 {
 public:
   explicit AnalyserNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 

--- a/dom/media/webaudio/AudioBufferSourceNode.cpp
+++ b/dom/media/webaudio/AudioBufferSourceNode.cpp
@@ -48,21 +48,21 @@ NS_IMPL_ADDREF_INHERITED(AudioBufferSour
 NS_IMPL_RELEASE_INHERITED(AudioBufferSourceNode, AudioNode)
 
 /**
  * Media-thread playback engine for AudioBufferSourceNode.
  * Nothing is played until a non-null buffer has been set (via
  * AudioNodeStream::SetBuffer) and a non-zero mBufferEnd has been set (via
  * AudioNodeStream::SetInt32Parameter).
  */
-class AudioBufferSourceNodeEngine : public AudioNodeEngine
+class AudioBufferSourceNodeEngine final : public AudioNodeEngine
 {
 public:
-  explicit AudioBufferSourceNodeEngine(AudioNode* aNode,
-                                       AudioDestinationNode* aDestination) :
+  AudioBufferSourceNodeEngine(AudioNode* aNode,
+                              AudioDestinationNode* aDestination) :
     AudioNodeEngine(aNode),
     mStart(0.0), mBeginProcessing(0),
     mStop(STREAM_TIME_MAX),
     mResampler(nullptr), mRemainingResamplerTail(0),
     mBufferEnd(0),
     mLoopStart(0), mLoopEnd(0),
     mBufferSampleRate(0), mBufferPosition(0), mChannels(0),
     mDopplerShift(1.0f),
@@ -708,22 +708,22 @@ AudioBufferSourceNode::Stop(double aWhen
 
   ns->SetStreamTimeParameter(STOP, Context(), std::max(0.0, aWhen));
 }
 
 void
 AudioBufferSourceNode::NotifyMainThreadStateChanged()
 {
   if (mStream->IsFinished()) {
-    class EndedEventDispatcher : public nsRunnable
+    class EndedEventDispatcher final : public nsRunnable
     {
     public:
       explicit EndedEventDispatcher(AudioBufferSourceNode* aNode)
         : mNode(aNode) {}
-      NS_IMETHODIMP Run()
+      NS_IMETHODIMP Run() override
       {
         // If it's not safe to run scripts right now, schedule this to run later
         if (!nsContentUtils::IsSafeToRunScript()) {
           nsContentUtils::AddScriptRunner(this);
           return NS_OK;
         }
 
         mNode->DispatchTrustedEvent(NS_LITERAL_STRING("ended"));

--- a/dom/media/webaudio/AudioBufferSourceNode.h
+++ b/dom/media/webaudio/AudioBufferSourceNode.h
@@ -10,18 +10,18 @@
 #include "AudioNode.h"
 #include "AudioBuffer.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioParam;
 
-class AudioBufferSourceNode : public AudioNode,
-                              public MainThreadMediaStreamListener
+class AudioBufferSourceNode final : public AudioNode,
+                                    public MainThreadMediaStreamListener
 {
 public:
   explicit AudioBufferSourceNode(AudioContext* aContext);
 
   virtual void DestroyMediaStream() override
   {
     if (mStream) {
       mStream->RemoveMainThreadListener(this);

--- a/dom/media/webaudio/AudioDestinationNode.cpp
+++ b/dom/media/webaudio/AudioDestinationNode.cpp
@@ -25,17 +25,17 @@
 #include "nsWidgetsCID.h"
 #include "mozilla/dom/Promise.h"
 
 namespace mozilla {
 namespace dom {
 
 static uint8_t gWebAudioOutputKey;
 
-class OfflineDestinationNodeEngine : public AudioNodeEngine
+class OfflineDestinationNodeEngine final : public AudioNodeEngine
 {
 public:
   typedef AutoFallibleTArray<nsAutoArrayPtr<float>, 2> InputChannels;
 
   OfflineDestinationNodeEngine(AudioDestinationNode* aNode,
                                uint32_t aNumberOfChannels,
                                uint32_t aLength,
                                float aSampleRate)
@@ -130,17 +130,17 @@ public:
   class OnCompleteTask final : public nsRunnable
   {
   public:
     OnCompleteTask(AudioContext* aAudioContext, AudioBuffer* aRenderedBuffer)
       : mAudioContext(aAudioContext)
       , mRenderedBuffer(aRenderedBuffer)
     {}
 
-    NS_IMETHOD Run()
+    NS_IMETHOD Run() override
     {
       nsRefPtr<OfflineAudioCompletionEvent> event =
           new OfflineAudioCompletionEvent(mAudioContext, nullptr, nullptr);
       event->InitEvent(mRenderedBuffer);
       mAudioContext->DispatchTrustedEvent(event);
 
       return NS_OK;
     }
@@ -205,27 +205,27 @@ private:
   uint32_t mWriteIndex;
   uint32_t mNumberOfChannels;
   // How many frames the OfflineAudioContext intends to produce.
   uint32_t mLength;
   float mSampleRate;
   bool mBufferAllocated;
 };
 
-class InputMutedRunnable : public nsRunnable
+class InputMutedRunnable final : public nsRunnable
 {
 public:
   InputMutedRunnable(AudioNodeStream* aStream,
                      bool aInputMuted)
     : mStream(aStream)
     , mInputMuted(aInputMuted)
   {
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() override
   {
     MOZ_ASSERT(NS_IsMainThread());
     nsRefPtr<AudioNode> node = mStream->Engine()->NodeMainThread();
 
     if (node) {
       nsRefPtr<AudioDestinationNode> destinationNode =
         static_cast<AudioDestinationNode*>(node.get());
       destinationNode->InputMuted(mInputMuted);
@@ -233,17 +233,17 @@ public:
     return NS_OK;
   }
 
 private:
   nsRefPtr<AudioNodeStream> mStream;
   bool mInputMuted;
 };
 
-class DestinationNodeEngine : public AudioNodeEngine
+class DestinationNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit DestinationNodeEngine(AudioDestinationNode* aNode)
     : AudioNodeEngine(aNode)
     , mVolume(1.0f)
     , mLastInputMuted(false)
   {
     MOZ_ASSERT(aNode);

--- a/dom/media/webaudio/AudioEventTimeline.h
+++ b/dom/media/webaudio/AudioEventTimeline.h
@@ -16,18 +16,20 @@
 #include "math.h"
 #include "WebAudioUtils.h"
 
 namespace mozilla {
 
 namespace dom {
 
 // This is an internal helper class and should not be used outside of this header.
-struct AudioTimelineEvent {
-  enum Type : uint32_t {
+struct AudioTimelineEvent final
+{
+  enum Type : uint32_t
+  {
     SetValue,
     LinearRamp,
     ExponentialRamp,
     SetTarget,
     SetValueCurve
   };
 
   AudioTimelineEvent(Type aType, double aTime, float aValue, double aTimeConstant = 0.0,

--- a/dom/media/webaudio/AudioNode.cpp
+++ b/dom/media/webaudio/AudioNode.cpp
@@ -320,17 +320,18 @@ AudioNode::Disconnect(uint32_t aOutput, 
     return;
   }
 
   // An upstream node may be starting to play on the graph thread, and the
   // engine for a downstream node may be sending a PlayingRefChangeHandler
   // ADDREF message to this (main) thread.  Wait for a round trip before
   // releasing nodes, to give engines receiving sound now time to keep their
   // nodes alive.
-  class RunnableRelease : public nsRunnable {
+  class RunnableRelease final : public nsRunnable
+  {
   public:
     explicit RunnableRelease(already_AddRefed<AudioNode> aNode)
       : mNode(aNode) {}
 
     NS_IMETHODIMP Run() override
     {
       mNode = nullptr;
       return NS_OK;

--- a/dom/media/webaudio/AudioNode.h
+++ b/dom/media/webaudio/AudioNode.h
@@ -69,17 +69,18 @@ public:
 
   // This should be idempotent (safe to call multiple times).
   virtual void DestroyMediaStream();
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(AudioNode,
                                            DOMEventTargetHelper)
 
-  virtual AudioBufferSourceNode* AsAudioBufferSourceNode() {
+  virtual AudioBufferSourceNode* AsAudioBufferSourceNode()
+  {
     return nullptr;
   }
 
   AudioContext* GetParentObject() const
   {
     return mContext;
   }
 
@@ -132,17 +133,18 @@ public:
     return mChannelInterpretation;
   }
   void SetChannelInterpretationValue(ChannelInterpretation aMode)
   {
     mChannelInterpretation = aMode;
     SendChannelMixingParametersToStream();
   }
 
-  struct InputNode {
+  struct InputNode final
+  {
     ~InputNode()
     {
       if (mStreamPort) {
         mStreamPort->Destroy();
       }
     }
 
     size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const

--- a/dom/media/webaudio/AudioNodeEngine.h
+++ b/dom/media/webaudio/AudioNodeEngine.h
@@ -22,27 +22,29 @@ class DelayNodeEngine;
 class AudioNodeStream;
 
 /**
  * This class holds onto a set of immutable channel buffers. The storage
  * for the buffers must be malloced, but the buffer pointers and the malloc
  * pointers can be different (e.g. if the buffers are contained inside
  * some malloced object).
  */
-class ThreadSharedFloatArrayBufferList : public ThreadSharedObject {
+class ThreadSharedFloatArrayBufferList final : public ThreadSharedObject
+{
 public:
   /**
    * Construct with null data.
    */
   explicit ThreadSharedFloatArrayBufferList(uint32_t aCount)
   {
     mContents.SetLength(aCount);
   }
 
-  struct Storage {
+  struct Storage final
+  {
     Storage() :
       mDataToFree(nullptr),
       mFree(nullptr),
       mSampleData(nullptr)
     {}
     ~Storage() {
       if (mFree) {
         mFree(mDataToFree);
@@ -229,17 +231,18 @@ AudioBlockPanStereoToStereo(const float 
  */
 float
 AudioBufferSumOfSquares(const float* aInput, uint32_t aLength);
 
 /**
  * All methods of this class and its subclasses are called on the
  * MediaStreamGraph thread.
  */
-class AudioNodeEngine {
+class AudioNodeEngine
+{
 public:
   // This should be compatible with AudioNodeStream::OutputChunks.
   typedef nsAutoTArray<AudioChunk, 1> OutputChunks;
 
   explicit AudioNodeEngine(dom::AudioNode* aNode)
     : mNode(aNode)
     , mNodeMutex("AudioNodeEngine::mNodeMutex")
     , mInputCount(aNode ? aNode->NumberOfInputs() : 1)

--- a/dom/media/webaudio/AudioNodeExternalInputStream.h
+++ b/dom/media/webaudio/AudioNodeExternalInputStream.h
@@ -13,24 +13,27 @@
 namespace mozilla {
 
 /**
  * This is a MediaStream implementation that acts for a Web Audio node but
  * unlike other AudioNodeStreams, supports any kind of MediaStream as an
  * input --- handling any number of audio tracks and handling blocking of
  * the input MediaStream.
  */
-class AudioNodeExternalInputStream : public AudioNodeStream {
+class AudioNodeExternalInputStream final : public AudioNodeStream
+{
 public:
-  AudioNodeExternalInputStream(AudioNodeEngine* aEngine, TrackRate aSampleRate, uint32_t aContextId);
+  AudioNodeExternalInputStream(AudioNodeEngine* aEngine, TrackRate aSampleRate,
+                               uint32_t aContextId);
 protected:
   ~AudioNodeExternalInputStream();
 
 public:
-  virtual void ProcessInput(GraphTime aFrom, GraphTime aTo, uint32_t aFlags) override;
+  virtual void ProcessInput(GraphTime aFrom, GraphTime aTo,
+                            uint32_t aFlags) override;
 
 private:
   /**
    * Determines if this is enabled or not.  Disabled nodes produce silence.
    * This node becomes disabled if the document principal does not subsume the
    * DOMMediaStream principal.
    */
   bool IsEnabled();

--- a/dom/media/webaudio/AudioNodeStream.cpp
+++ b/dom/media/webaudio/AudioNodeStream.cpp
@@ -90,23 +90,25 @@ AudioNodeStream::SizeOfAudioNodesIncludi
     mEngine->SizeOfIncludingThis(aMallocSizeOf, aUsage);
   }
 }
 
 void
 AudioNodeStream::SetStreamTimeParameter(uint32_t aIndex, AudioContext* aContext,
                                         double aStreamTime)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, uint32_t aIndex, MediaStream* aRelativeToStream,
             double aStreamTime)
       : ControlMessage(aStream), mStreamTime(aStreamTime),
-        mRelativeToStream(aRelativeToStream), mIndex(aIndex) {}
-    virtual void Run()
+        mRelativeToStream(aRelativeToStream), mIndex(aIndex)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->
           SetStreamTimeParameterImpl(mIndex, mRelativeToStream, mStreamTime);
     }
     double mStreamTime;
     MediaStream* mRelativeToStream;
     uint32_t mIndex;
   };
@@ -122,151 +124,163 @@ AudioNodeStream::SetStreamTimeParameterI
 {
   StreamTime ticks = TicksFromDestinationTime(aRelativeToStream, aStreamTime);
   mEngine->SetStreamTimeParameter(aIndex, ticks);
 }
 
 void
 AudioNodeStream::SetDoubleParameter(uint32_t aIndex, double aValue)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, uint32_t aIndex, double aValue)
-      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex) {}
-    virtual void Run()
+      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->
           SetDoubleParameter(mIndex, mValue);
     }
     double mValue;
     uint32_t mIndex;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aIndex, aValue));
 }
 
 void
 AudioNodeStream::SetInt32Parameter(uint32_t aIndex, int32_t aValue)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, uint32_t aIndex, int32_t aValue)
-      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex) {}
-    virtual void Run()
+      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->
           SetInt32Parameter(mIndex, mValue);
     }
     int32_t mValue;
     uint32_t mIndex;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aIndex, aValue));
 }
 
 void
 AudioNodeStream::SetTimelineParameter(uint32_t aIndex,
                                       const AudioParamTimeline& aValue)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, uint32_t aIndex,
             const AudioParamTimeline& aValue)
       : ControlMessage(aStream),
         mValue(aValue),
         mSampleRate(aStream->SampleRate()),
-        mIndex(aIndex) {}
-    virtual void Run()
+        mIndex(aIndex)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->
           SetTimelineParameter(mIndex, mValue, mSampleRate);
     }
     AudioParamTimeline mValue;
     TrackRate mSampleRate;
     uint32_t mIndex;
   };
   GraphImpl()->AppendMessage(new Message(this, aIndex, aValue));
 }
 
 void
 AudioNodeStream::SetThreeDPointParameter(uint32_t aIndex, const ThreeDPoint& aValue)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, uint32_t aIndex, const ThreeDPoint& aValue)
-      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex) {}
-    virtual void Run()
+      : ControlMessage(aStream), mValue(aValue), mIndex(aIndex)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->
           SetThreeDPointParameter(mIndex, mValue);
     }
     ThreeDPoint mValue;
     uint32_t mIndex;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aIndex, aValue));
 }
 
 void
 AudioNodeStream::SetBuffer(already_AddRefed<ThreadSharedFloatArrayBufferList>&& aBuffer)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream,
             already_AddRefed<ThreadSharedFloatArrayBufferList>& aBuffer)
-      : ControlMessage(aStream), mBuffer(aBuffer) {}
-    virtual void Run()
+      : ControlMessage(aStream), mBuffer(aBuffer)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->
           SetBuffer(mBuffer.forget());
     }
     nsRefPtr<ThreadSharedFloatArrayBufferList> mBuffer;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aBuffer));
 }
 
 void
 AudioNodeStream::SetRawArrayData(nsTArray<float>& aData)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream,
             nsTArray<float>& aData)
       : ControlMessage(aStream)
     {
       mData.SwapElements(aData);
     }
-    virtual void Run()
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->Engine()->SetRawArrayData(mData);
     }
     nsTArray<float> mData;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aData));
 }
 
 void
 AudioNodeStream::SetChannelMixingParameters(uint32_t aNumberOfChannels,
                                             ChannelCountMode aChannelCountMode,
                                             ChannelInterpretation aChannelInterpretation)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream,
             uint32_t aNumberOfChannels,
             ChannelCountMode aChannelCountMode,
             ChannelInterpretation aChannelInterpretation)
       : ControlMessage(aStream),
         mNumberOfChannels(aNumberOfChannels),
         mChannelCountMode(aChannelCountMode),
         mChannelInterpretation(aChannelInterpretation)
     {}
-    virtual void Run()
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->
         SetChannelMixingParametersImpl(mNumberOfChannels, mChannelCountMode,
                                        mChannelInterpretation);
     }
     uint32_t mNumberOfChannels;
     ChannelCountMode mChannelCountMode;
     ChannelInterpretation mChannelInterpretation;
@@ -275,21 +289,23 @@ AudioNodeStream::SetChannelMixingParamet
   GraphImpl()->AppendMessage(new Message(this, aNumberOfChannels,
                                          aChannelCountMode,
                                          aChannelInterpretation));
 }
 
 void
 AudioNodeStream::SetPassThrough(bool aPassThrough)
 {
-  class Message : public ControlMessage {
+  class Message final : public ControlMessage
+  {
   public:
     Message(AudioNodeStream* aStream, bool aPassThrough)
-      : ControlMessage(aStream), mPassThrough(aPassThrough) {}
-    virtual void Run()
+      : ControlMessage(aStream), mPassThrough(aPassThrough)
+    {}
+    virtual void Run() override
     {
       static_cast<AudioNodeStream*>(mStream)->mPassThrough = mPassThrough;
     }
     bool mPassThrough;
   };
 
   GraphImpl()->AppendMessage(new Message(this, aPassThrough));
 }

--- a/dom/media/webaudio/AudioNodeStream.h
+++ b/dom/media/webaudio/AudioNodeStream.h
@@ -26,17 +26,18 @@ class AudioNodeEngine;
  * The start time of the AudioTrack is aligned to the start time of the
  * AudioContext's destination node stream, plus some multiple of BLOCK_SIZE
  * samples.
  *
  * An AudioNodeStream has an AudioNodeEngine plugged into it that does the
  * actual audio processing. AudioNodeStream contains the glue code that
  * integrates audio processing with the MediaStreamGraph.
  */
-class AudioNodeStream : public ProcessedMediaStream {
+class AudioNodeStream : public ProcessedMediaStream
+{
   typedef dom::ChannelCountMode ChannelCountMode;
   typedef dom::ChannelInterpretation ChannelInterpretation;
 
 public:
   typedef mozilla::dom::AudioContext AudioContext;
 
   enum { AUDIO_TRACK = 1 };
 

--- a/dom/media/webaudio/AudioProcessingEvent.h
+++ b/dom/media/webaudio/AudioProcessingEvent.h
@@ -9,17 +9,17 @@
 
 #include "AudioBuffer.h"
 #include "ScriptProcessorNode.h"
 #include "mozilla/dom/Event.h"
 
 namespace mozilla {
 namespace dom {
 
-class AudioProcessingEvent : public Event
+class AudioProcessingEvent final : public Event
 {
 public:
   AudioProcessingEvent(ScriptProcessorNode* aOwner,
                        nsPresContext* aPresContext,
                        WidgetEvent* aEvent);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_FORWARD_TO_EVENT

--- a/dom/media/webaudio/BiquadFilterNode.cpp
+++ b/dom/media/webaudio/BiquadFilterNode.cpp
@@ -68,17 +68,17 @@ SetParamsOnBiquad(WebCore::Biquad& aBiqu
     aBiquad.setAllpassParams(normalizedFrequency, aQ);
     break;
   default:
     NS_NOTREACHED("We should never see the alternate names here");
     break;
   }
 }
 
-class BiquadFilterNodeEngine : public AudioNodeEngine
+class BiquadFilterNodeEngine final : public AudioNodeEngine
 {
 public:
   BiquadFilterNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     // Keep the default values in sync with the default values in
     // BiquadFilterNode::BiquadFilterNode

--- a/dom/media/webaudio/BiquadFilterNode.h
+++ b/dom/media/webaudio/BiquadFilterNode.h
@@ -11,17 +11,17 @@
 #include "AudioParam.h"
 #include "mozilla/dom/BiquadFilterNodeBinding.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class BiquadFilterNode : public AudioNode
+class BiquadFilterNode final : public AudioNode
 {
 public:
   explicit BiquadFilterNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(BiquadFilterNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/BufferDecoder.h
+++ b/dom/media/webaudio/BufferDecoder.h
@@ -13,17 +13,17 @@
 #include "mozilla/ReentrantMonitor.h"
 
 namespace mozilla {
 
 /**
  * This class provides a decoder object which decodes a media file that lives in
  * a memory buffer.
  */
-class BufferDecoder : public AbstractMediaDecoder
+class BufferDecoder final : public AbstractMediaDecoder
 {
 public:
   // This class holds a weak pointer to MediaResource.  It's the responsibility
   // of the caller to manage the memory of the MediaResource object.
   explicit BufferDecoder(MediaResource* aResource);
 
   NS_DECL_THREADSAFE_ISUPPORTS
 

--- a/dom/media/webaudio/ChannelMergerNode.cpp
+++ b/dom/media/webaudio/ChannelMergerNode.cpp
@@ -9,17 +9,17 @@
 #include "AudioNodeEngine.h"
 #include "AudioNodeStream.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_ISUPPORTS_INHERITED0(ChannelMergerNode, AudioNode)
 
-class ChannelMergerNodeEngine : public AudioNodeEngine
+class ChannelMergerNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit ChannelMergerNodeEngine(ChannelMergerNode* aNode)
     : AudioNodeEngine(aNode)
   {
     MOZ_ASSERT(NS_IsMainThread());
   }
 

--- a/dom/media/webaudio/ChannelMergerNode.h
+++ b/dom/media/webaudio/ChannelMergerNode.h
@@ -9,17 +9,17 @@
 
 #include "AudioNode.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class ChannelMergerNode : public AudioNode
+class ChannelMergerNode final : public AudioNode
 {
 public:
   ChannelMergerNode(AudioContext* aContext,
                     uint16_t aInputCount);
 
   NS_DECL_ISUPPORTS_INHERITED
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/ChannelSplitterNode.cpp
+++ b/dom/media/webaudio/ChannelSplitterNode.cpp
@@ -9,17 +9,17 @@
 #include "AudioNodeEngine.h"
 #include "AudioNodeStream.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_ISUPPORTS_INHERITED0(ChannelSplitterNode, AudioNode)
 
-class ChannelSplitterNodeEngine : public AudioNodeEngine
+class ChannelSplitterNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit ChannelSplitterNodeEngine(ChannelSplitterNode* aNode)
     : AudioNodeEngine(aNode)
   {
     MOZ_ASSERT(NS_IsMainThread());
   }
 

--- a/dom/media/webaudio/ChannelSplitterNode.h
+++ b/dom/media/webaudio/ChannelSplitterNode.h
@@ -9,17 +9,17 @@
 
 #include "AudioNode.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class ChannelSplitterNode : public AudioNode
+class ChannelSplitterNode final : public AudioNode
 {
 public:
   ChannelSplitterNode(AudioContext* aContext,
                       uint16_t aOutputCount);
 
   NS_DECL_ISUPPORTS_INHERITED
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/ConvolverNode.cpp
+++ b/dom/media/webaudio/ConvolverNode.cpp
@@ -17,17 +17,17 @@ namespace dom {
 NS_IMPL_CYCLE_COLLECTION_INHERITED(ConvolverNode, AudioNode, mBuffer)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(ConvolverNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(ConvolverNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(ConvolverNode, AudioNode)
 
-class ConvolverNodeEngine : public AudioNodeEngine
+class ConvolverNodeEngine final : public AudioNodeEngine
 {
   typedef PlayingRefChangeHandler PlayingRefChanged;
 public:
   ConvolverNodeEngine(AudioNode* aNode, bool aNormalize)
     : AudioNodeEngine(aNode)
     , mBufferLength(0)
     , mLeftOverData(INT32_MIN)
     , mSampleRate(0.0f)

--- a/dom/media/webaudio/ConvolverNode.h
+++ b/dom/media/webaudio/ConvolverNode.h
@@ -8,17 +8,17 @@
 #define ConvolverNode_h_
 
 #include "AudioNode.h"
 #include "AudioBuffer.h"
 
 namespace mozilla {
 namespace dom {
 
-class ConvolverNode : public AudioNode
+class ConvolverNode final : public AudioNode
 {
 public:
   explicit ConvolverNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ConvolverNode, AudioNode);
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/DelayBuffer.h
+++ b/dom/media/webaudio/DelayBuffer.h
@@ -8,17 +8,18 @@
 #define DelayBuffer_h_
 
 #include "nsTArray.h"
 #include "AudioSegment.h"
 #include "mozilla/dom/AudioNodeBinding.h" // for ChannelInterpretation
 
 namespace mozilla {
 
-class DelayBuffer {
+class DelayBuffer final
+{
   typedef dom::ChannelInterpretation ChannelInterpretation;
 
 public:
   // See WebAudioUtils::ComputeSmoothingRate() for frame to frame exponential
   // |smoothingRate| multiplier.
   DelayBuffer(double aMaxDelayTicks, double aSmoothingRate)
     : mSmoothingRate(aSmoothingRate)
     , mCurrentDelay(-1.0)

--- a/dom/media/webaudio/DelayNode.cpp
+++ b/dom/media/webaudio/DelayNode.cpp
@@ -20,17 +20,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(Delay
                                    mDelay)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(DelayNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(DelayNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(DelayNode, AudioNode)
 
-class DelayNodeEngine : public AudioNodeEngine
+class DelayNodeEngine final : public AudioNodeEngine
 {
   typedef PlayingRefChangeHandler PlayingRefChanged;
 public:
   DelayNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination,
                   double aMaxDelayTicks)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))

--- a/dom/media/webaudio/DelayNode.h
+++ b/dom/media/webaudio/DelayNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "AudioParam.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class DelayNode : public AudioNode
+class DelayNode final : public AudioNode
 {
 public:
   DelayNode(AudioContext* aContext, double aMaxDelay);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DelayNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/DynamicsCompressorNode.cpp
+++ b/dom/media/webaudio/DynamicsCompressorNode.cpp
@@ -25,17 +25,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(Dynam
                                    mRelease)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(DynamicsCompressorNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(DynamicsCompressorNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(DynamicsCompressorNode, AudioNode)
 
-class DynamicsCompressorNodeEngine : public AudioNodeEngine
+class DynamicsCompressorNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit DynamicsCompressorNodeEngine(AudioNode* aNode,
                                         AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     // Keep the default value in sync with the default value in
@@ -146,26 +146,26 @@ public:
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
 
 private:
   void SendReductionParamToMainThread(AudioNodeStream* aStream, float aReduction)
   {
     MOZ_ASSERT(!NS_IsMainThread());
 
-    class Command : public nsRunnable
+    class Command final : public nsRunnable
     {
     public:
       Command(AudioNodeStream* aStream, float aReduction)
         : mStream(aStream)
         , mReduction(aReduction)
       {
       }
 
-      NS_IMETHODIMP Run()
+      NS_IMETHOD Run() override
       {
         nsRefPtr<DynamicsCompressorNode> node;
         {
           // No need to keep holding the lock for the whole duration of this
           // function, since we're holding a strong reference to it, so if
           // we can obtain the reference, we will hold the node alive in
           // this function.
           MutexAutoLock lock(mStream->Engine()->NodeMutex());

--- a/dom/media/webaudio/DynamicsCompressorNode.h
+++ b/dom/media/webaudio/DynamicsCompressorNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "AudioParam.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class DynamicsCompressorNode : public AudioNode
+class DynamicsCompressorNode final : public AudioNode
 {
 public:
   explicit DynamicsCompressorNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DynamicsCompressorNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/FFTBlock.h
+++ b/dom/media/webaudio/FFTBlock.h
@@ -11,17 +11,18 @@
 #include "AudioNodeEngine.h"
 #include "kiss_fft/kiss_fftr.h"
 
 namespace mozilla {
 
 // This class defines an FFT block, loosely modeled after Blink's FFTFrame
 // class to make sharing code with Blink easy.
 // Currently it's implemented on top of KissFFT on all platforms.
-class FFTBlock {
+class FFTBlock final
+{
 public:
   explicit FFTBlock(uint32_t aFFTSize)
     : mFFT(nullptr)
     , mIFFT(nullptr)
     , mFFTSize(aFFTSize)
   {
     MOZ_COUNT_CTOR(FFTBlock);
     mOutputBuffer.SetLength(aFFTSize / 2 + 1);

--- a/dom/media/webaudio/GainNode.cpp
+++ b/dom/media/webaudio/GainNode.cpp
@@ -18,17 +18,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(GainN
                                    mGain)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(GainNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(GainNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(GainNode, AudioNode)
 
-class GainNodeEngine : public AudioNodeEngine
+class GainNodeEngine final : public AudioNodeEngine
 {
 public:
   GainNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     // Keep the default value in sync with the default value in GainNode::GainNode.
     , mGain(1.f)

--- a/dom/media/webaudio/GainNode.h
+++ b/dom/media/webaudio/GainNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "AudioParam.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class GainNode : public AudioNode
+class GainNode final : public AudioNode
 {
 public:
   explicit GainNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(GainNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/MediaBufferDecoder.cpp
+++ b/dom/media/webaudio/MediaBufferDecoder.cpp
@@ -45,17 +45,17 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(WebAudioDecodeJob)
 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(WebAudioDecodeJob, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(WebAudioDecodeJob, Release)
 
 using namespace dom;
 
-class ReportResultTask : public nsRunnable
+class ReportResultTask final : public nsRunnable
 {
 public:
   ReportResultTask(WebAudioDecodeJob& aDecodeJob,
                    WebAudioDecodeJob::ResultFn aFunction,
                    WebAudioDecodeJob::ErrorCode aErrorCode)
     : mDecodeJob(aDecodeJob)
     , mFunction(aFunction)
     , mErrorCode(aErrorCode)
@@ -77,23 +77,24 @@ private:
   // Therefore, it is not safe to do anything fancy with it in this class.
   // Really, this class is only used because nsRunnableMethod doesn't support
   // methods accepting arguments.
   WebAudioDecodeJob& mDecodeJob;
   WebAudioDecodeJob::ResultFn mFunction;
   WebAudioDecodeJob::ErrorCode mErrorCode;
 };
 
-enum class PhaseEnum : int {
+enum class PhaseEnum : int
+{
   Decode,
   AllocateBuffer,
   Done
 };
 
-class MediaDecodeTask : public nsRunnable
+class MediaDecodeTask final : public nsRunnable
 {
 public:
   MediaDecodeTask(const char* aContentType, uint8_t* aBuffer,
                   uint32_t aLength,
                   WebAudioDecodeJob& aDecodeJob)
     : mContentType(aContentType)
     , mBuffer(aBuffer)
     , mLength(aLength)
@@ -209,17 +210,18 @@ MediaDecodeTask::CreateReader()
 
   if (!mDecoderReader->EnsureTaskQueue()) {
     return false;
   }
 
   return true;
 }
 
-class AutoResampler {
+class AutoResampler final
+{
 public:
   AutoResampler()
     : mResampler(nullptr)
   {}
   ~AutoResampler()
   {
     if (mResampler) {
       speex_resampler_destroy(mResampler);

--- a/dom/media/webaudio/MediaElementAudioSourceNode.h
+++ b/dom/media/webaudio/MediaElementAudioSourceNode.h
@@ -7,17 +7,17 @@
 #ifndef MediaElementAudioSourceNode_h_
 #define MediaElementAudioSourceNode_h_
 
 #include "MediaStreamAudioSourceNode.h"
 
 namespace mozilla {
 namespace dom {
 
-class MediaElementAudioSourceNode : public MediaStreamAudioSourceNode
+class MediaElementAudioSourceNode final : public MediaStreamAudioSourceNode
 {
 public:
   MediaElementAudioSourceNode(AudioContext* aContext,
                               DOMMediaStream* aStream);
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   virtual const char* NodeType() const override

--- a/dom/media/webaudio/MediaStreamAudioDestinationNode.h
+++ b/dom/media/webaudio/MediaStreamAudioDestinationNode.h
@@ -7,17 +7,17 @@
 #ifndef MediaStreamAudioDestinationNode_h_
 #define MediaStreamAudioDestinationNode_h_
 
 #include "AudioNode.h"
 
 namespace mozilla {
 namespace dom {
 
-class MediaStreamAudioDestinationNode : public AudioNode
+class MediaStreamAudioDestinationNode final : public AudioNode
 {
 public:
   explicit MediaStreamAudioDestinationNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaStreamAudioDestinationNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/MediaStreamAudioSourceNode.h
+++ b/dom/media/webaudio/MediaStreamAudioSourceNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "DOMMediaStream.h"
 #include "AudioNodeEngine.h"
 
 namespace mozilla {
 
 namespace dom {
 
-class MediaStreamAudioSourceNodeEngine : public AudioNodeEngine
+class MediaStreamAudioSourceNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit MediaStreamAudioSourceNodeEngine(AudioNode* aNode)
     : AudioNodeEngine(aNode), mEnabled(false) {}
 
   bool IsEnabled() const { return mEnabled; }
   enum Parameters {
     ENABLE

--- a/dom/media/webaudio/OfflineAudioCompletionEvent.h
+++ b/dom/media/webaudio/OfflineAudioCompletionEvent.h
@@ -10,17 +10,17 @@
 #include "AudioBuffer.h"
 #include "mozilla/dom/Event.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class OfflineAudioCompletionEvent : public Event
+class OfflineAudioCompletionEvent final : public Event
 {
 public:
   OfflineAudioCompletionEvent(AudioContext* aOwner,
                               nsPresContext* aPresContext,
                               WidgetEvent* aEvent);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_FORWARD_TO_EVENT

--- a/dom/media/webaudio/OscillatorNode.cpp
+++ b/dom/media/webaudio/OscillatorNode.cpp
@@ -18,17 +18,17 @@ NS_IMPL_CYCLE_COLLECTION_INHERITED(Oscil
                                    mPeriodicWave, mFrequency, mDetune)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(OscillatorNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(OscillatorNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(OscillatorNode, AudioNode)
 
-class OscillatorNodeEngine : public AudioNodeEngine
+class OscillatorNodeEngine final : public AudioNodeEngine
 {
 public:
   OscillatorNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     , mStart(-1)
     , mStop(STREAM_TIME_MAX)
@@ -510,22 +510,22 @@ OscillatorNode::Stop(double aWhen, Error
   ns->SetStreamTimeParameter(OscillatorNodeEngine::STOP,
                              Context(), std::max(0.0, aWhen));
 }
 
 void
 OscillatorNode::NotifyMainThreadStateChanged()
 {
   if (mStream->IsFinished()) {
-    class EndedEventDispatcher : public nsRunnable
+    class EndedEventDispatcher final : public nsRunnable
     {
     public:
       explicit EndedEventDispatcher(OscillatorNode* aNode)
         : mNode(aNode) {}
-      NS_IMETHODIMP Run()
+      NS_IMETHOD Run() override
       {
         // If it's not safe to run scripts right now, schedule this to run later
         if (!nsContentUtils::IsSafeToRunScript()) {
           nsContentUtils::AddScriptRunner(this);
           return NS_OK;
         }
 
         mNode->DispatchTrustedEvent(NS_LITERAL_STRING("ended"));

--- a/dom/media/webaudio/OscillatorNode.h
+++ b/dom/media/webaudio/OscillatorNode.h
@@ -13,18 +13,18 @@
 #include "mozilla/dom/OscillatorNodeBinding.h"
 #include "mozilla/Preferences.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class OscillatorNode : public AudioNode,
-                       public MainThreadMediaStreamListener
+class OscillatorNode final : public AudioNode,
+                             public MainThreadMediaStreamListener
 {
 public:
   explicit OscillatorNode(AudioContext* aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(OscillatorNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;

--- a/dom/media/webaudio/PannerNode.cpp
+++ b/dom/media/webaudio/PannerNode.cpp
@@ -34,17 +34,17 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(PannerNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(PannerNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(PannerNode, AudioNode)
 
-class PannerNodeEngine : public AudioNodeEngine
+class PannerNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit PannerNodeEngine(AudioNode* aNode)
     : AudioNodeEngine(aNode)
     // Please keep these default values consistent with PannerNode::PannerNode below.
     , mPanningModelFunction(&PannerNodeEngine::EqualPowerPanningFunction)
     , mDistanceModelFunction(&PannerNodeEngine::InverseGainFunction)
     , mPosition()

--- a/dom/media/webaudio/PannerNode.h
+++ b/dom/media/webaudio/PannerNode.h
@@ -16,18 +16,18 @@
 #include <set>
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 class AudioBufferSourceNode;
 
-class PannerNode : public AudioNode,
-                   public SupportsWeakPtr<PannerNode>
+class PannerNode final : public AudioNode,
+                         public SupportsWeakPtr<PannerNode>
 {
 public:
   MOZ_DECLARE_WEAKREFERENCE_TYPENAME(PannerNode)
   explicit PannerNode(AudioContext* aContext);
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   virtual void DestroyMediaStream() override;

--- a/dom/media/webaudio/PlayingRefChangeHandler.h
+++ b/dom/media/webaudio/PlayingRefChangeHandler.h
@@ -8,17 +8,17 @@
 #define PlayingRefChangeHandler_h__
 
 #include "nsThreadUtils.h"
 #include "AudioNodeStream.h"
 
 namespace mozilla {
 namespace dom {
 
-class PlayingRefChangeHandler : public nsRunnable
+class PlayingRefChangeHandler final : public nsRunnable
 {
 public:
   enum ChangeType { ADDREF, RELEASE };
   PlayingRefChangeHandler(AudioNodeStream* aStream, ChangeType aChange)
     : mStream(aStream)
     , mChange(aChange)
   {
   }

--- a/dom/media/webaudio/ReportDecodeResultTask.h
+++ b/dom/media/webaudio/ReportDecodeResultTask.h
@@ -7,17 +7,17 @@
 #ifndef ReportDecodeResultTask_h_
 #define ReportDecodeResultTask_h_
 
 #include "mozilla/Attributes.h"
 #include "MediaBufferDecoder.h"
 
 namespace mozilla {
 
-class ReportDecodeResultTask : public nsRunnable
+class ReportDecodeResultTask final : public nsRunnable
 {
 public:
   ReportDecodeResultTask(DecodeJob& aDecodeJob,
                          DecodeJob::ResultFn aFunction)
     : mDecodeJob(aDecodeJob)
     , mFunction(aFunction)
   {
     MOZ_ASSERT(aFunction);

--- a/dom/media/webaudio/ScriptProcessorNode.cpp
+++ b/dom/media/webaudio/ScriptProcessorNode.cpp
@@ -23,20 +23,20 @@ namespace dom {
 // The maximum latency, in seconds, that we can live with before dropping
 // buffers.
 static const float MAX_LATENCY_S = 0.5;
 
 NS_IMPL_ISUPPORTS_INHERITED0(ScriptProcessorNode, AudioNode)
 
 // This class manages a queue of output buffers shared between
 // the main thread and the Media Stream Graph thread.
-class SharedBuffers
+class SharedBuffers final
 {
 private:
-  class OutputQueue
+  class OutputQueue final
   {
   public:
     explicit OutputQueue(const char* aName)
       : mMutex(aName)
     {}
 
     size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
     {
@@ -232,17 +232,17 @@ private:
   float mLatency;
   // This is the time at which we last produced a buffer, to detect if the main
   // thread has been blocked.
   TimeStamp mLastEventTime;
   // True if we should be dropping buffers.
   bool mDroppingBuffers;
 };
 
-class ScriptProcessorNodeEngine : public AudioNodeEngine
+class ScriptProcessorNodeEngine final : public AudioNodeEngine
 {
 public:
   typedef nsAutoTArray<nsAutoArrayPtr<float>, 2> InputChannels;
 
   ScriptProcessorNodeEngine(ScriptProcessorNode* aNode,
                             AudioDestinationNode* aDestination,
                             uint32_t aBufferSize,
                             uint32_t aNumberOfInputChannels)
@@ -356,17 +356,17 @@ private:
     // Add the duration of the current sample
     playbackTick += WEBAUDIO_BLOCK_SIZE;
     // Add the delay caused by the main thread
     playbackTick += mSharedBuffers->DelaySoFar();
     // Compute the playback time in the coordinate system of the destination
     double playbackTime =
       mSource->DestinationTimeFromTicks(mDestination, playbackTick);
 
-    class Command : public nsRunnable
+    class Command final : public nsRunnable
     {
     public:
       Command(AudioNodeStream* aStream,
               InputChannels& aInputChannels,
               double aPlaybackTime,
               bool aNullInput)
         : mStream(aStream)
         , mPlaybackTime(aPlaybackTime)
@@ -375,17 +375,17 @@ private:
         mInputChannels.SetLength(aInputChannels.Length());
         if (!aNullInput) {
           for (uint32_t i = 0; i < mInputChannels.Length(); ++i) {
             mInputChannels[i] = aInputChannels[i].forget();
           }
         }
       }
 
-      NS_IMETHODIMP Run()
+      NS_IMETHOD Run() override
       {
         nsRefPtr<ScriptProcessorNode> node = static_cast<ScriptProcessorNode*>
           (mStream->Engine()->NodeMainThread());
         if (!node) {
           return NS_OK;
         }
         AudioContext* context = node->Context();
         if (!context) {

--- a/dom/media/webaudio/ScriptProcessorNode.h
+++ b/dom/media/webaudio/ScriptProcessorNode.h
@@ -11,17 +11,17 @@
 #include "nsAutoPtr.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 class SharedBuffers;
 
-class ScriptProcessorNode : public AudioNode
+class ScriptProcessorNode final : public AudioNode
 {
 public:
   ScriptProcessorNode(AudioContext* aContext,
                       uint32_t aBufferSize,
                       uint32_t aNumberOfInputChannels,
                       uint32_t aNumberOfOutputChannels);
 
   NS_DECL_ISUPPORTS_INHERITED

--- a/dom/media/webaudio/StereoPannerNode.cpp
+++ b/dom/media/webaudio/StereoPannerNode.cpp
@@ -22,17 +22,17 @@ using namespace std;
 NS_IMPL_CYCLE_COLLECTION_INHERITED(StereoPannerNode, AudioNode, mPan)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(StereoPannerNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 
 NS_IMPL_ADDREF_INHERITED(StereoPannerNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(StereoPannerNode, AudioNode)
 
-class StereoPannerNodeEngine : public AudioNodeEngine
+class StereoPannerNodeEngine final : public AudioNodeEngine
 {
 public:
   StereoPannerNodeEngine(AudioNode* aNode,
                          AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*>(aDestination->Stream()))
     // Keep the default value in sync with the default value in

--- a/dom/media/webaudio/StereoPannerNode.h
+++ b/dom/media/webaudio/StereoPannerNode.h
@@ -10,17 +10,17 @@
 #include "AudioNode.h"
 #include "mozilla/dom/StereoPannerNodeBinding.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class StereoPannerNode : public AudioNode
+class StereoPannerNode final : public AudioNode
 {
 public:
   MOZ_DECLARE_REFCOUNTED_TYPENAME(StereoPannerNode)
   explicit StereoPannerNode(AudioContext* aContext);
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   virtual void SetChannelCount(uint32_t aChannelCount, ErrorResult& aRv) override

--- a/dom/media/webaudio/ThreeDPoint.h
+++ b/dom/media/webaudio/ThreeDPoint.h
@@ -9,17 +9,18 @@
 
 #include <cmath>
 #include <algorithm>
 
 namespace mozilla {
 
 namespace dom {
 
-struct ThreeDPoint {
+struct ThreeDPoint final
+{
   ThreeDPoint()
     : x(0.)
     , y(0.)
     , z(0.)
   {
   }
   ThreeDPoint(double aX, double aY, double aZ)
     : x(aX)

--- a/dom/media/webaudio/WaveShaperNode.cpp
+++ b/dom/media/webaudio/WaveShaperNode.cpp
@@ -43,17 +43,17 @@ static uint32_t ValueOf(OverSampleType a
   case OverSampleType::_2x:  return 2;
   case OverSampleType::_4x:  return 4;
   default:
     NS_NOTREACHED("We should never reach here");
     return 1;
   }
 }
 
-class Resampler
+class Resampler final
 {
 public:
   Resampler()
     : mType(OverSampleType::None)
     , mUpSampler(nullptr)
     , mDownSampler(nullptr)
     , mChannels(0)
     , mSampleRate(0)
@@ -156,17 +156,17 @@ private:
   OverSampleType mType;
   SpeexResamplerState* mUpSampler;
   SpeexResamplerState* mDownSampler;
   uint32_t mChannels;
   TrackRate mSampleRate;
   nsTArray<float> mBuffer;
 };
 
-class WaveShaperNodeEngine : public AudioNodeEngine
+class WaveShaperNodeEngine final : public AudioNodeEngine
 {
 public:
   explicit WaveShaperNodeEngine(AudioNode* aNode)
     : AudioNodeEngine(aNode)
     , mType(OverSampleType::None)
   {
   }
 

--- a/dom/media/webaudio/WaveShaperNode.h
+++ b/dom/media/webaudio/WaveShaperNode.h
@@ -11,17 +11,17 @@
 #include "mozilla/dom/WaveShaperNodeBinding.h"
 #include "mozilla/dom/TypedArray.h"
 
 namespace mozilla {
 namespace dom {
 
 class AudioContext;
 
-class WaveShaperNode : public AudioNode
+class WaveShaperNode final : public AudioNode
 {
 public:
   explicit WaveShaperNode(AudioContext *aContext);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(WaveShaperNode, AudioNode)
 
   virtual JSObject* WrapObject(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;