diff --git a/dom/media/platforms/wmf/MFMediaEngineStream.cpp b/dom/media/platforms/wmf/MFMediaEngineStream.cpp
index adb869ff195f..cf12c1aec6cf 100644
--- a/dom/media/platforms/wmf/MFMediaEngineStream.cpp
+++ b/dom/media/platforms/wmf/MFMediaEngineStream.cpp
@@ -133,9 +133,14 @@ MFMediaEngineStreamWrapper::FakeDecodedDataCreator::FakeDecodedDataCreator(
 }
 
 MFMediaEngineStream::MFMediaEngineStream()
-    : mIsShutdown(false), mIsSelected(false), mReceivedEOS(false) {}
+    : mIsShutdown(false), mIsSelected(false), mReceivedEOS(false) {
+  MOZ_COUNT_CTOR(MFMediaEngineStream);
+}
 
-MFMediaEngineStream::~MFMediaEngineStream() { MOZ_ASSERT(IsShutdown()); }
+MFMediaEngineStream::~MFMediaEngineStream() {
+  MOZ_ASSERT(IsShutdown());
+  MOZ_COUNT_DTOR(MFMediaEngineStream);
+}
 
 HRESULT MFMediaEngineStream::RuntimeClassInitialize(
     uint64_t aStreamId, const TrackInfo& aInfo, MFMediaSource* aParentSource) {
diff --git a/dom/media/platforms/wmf/MFMediaSource.cpp b/dom/media/platforms/wmf/MFMediaSource.cpp
index 05aa12b9d41a..bf8e892ccc8d 100644
--- a/dom/media/platforms/wmf/MFMediaSource.cpp
+++ b/dom/media/platforms/wmf/MFMediaSource.cpp
@@ -26,7 +26,11 @@ namespace mozilla {
 using Microsoft::WRL::ComPtr;
 
 MFMediaSource::MFMediaSource()
-    : mPresentationEnded(false), mIsAudioEnded(false), mIsVideoEnded(false) {}
+    : mPresentationEnded(false), mIsAudioEnded(false), mIsVideoEnded(false) {
+  MOZ_COUNT_CTOR(MFMediaSource);
+}
+
+MFMediaSource::~MFMediaSource() { MOZ_COUNT_DTOR(MFMediaSource); }
 
 HRESULT MFMediaSource::RuntimeClassInitialize(
     const Maybe<AudioInfo>& aAudio, const Maybe<VideoInfo>& aVideo,
diff --git a/dom/media/platforms/wmf/MFMediaSource.h b/dom/media/platforms/wmf/MFMediaSource.h
index 3cd3e4c825c1..bf11ecfae322 100644
--- a/dom/media/platforms/wmf/MFMediaSource.h
+++ b/dom/media/platforms/wmf/MFMediaSource.h
@@ -41,6 +41,8 @@ class MFMediaSource
           IMFMediaSource, IMFRateControl, IMFRateSupport, IMFGetService> {
  public:
   MFMediaSource();
+  ~MFMediaSource();
+
   HRESULT RuntimeClassInitialize(const Maybe<AudioInfo>& aAudio,
                                  const Maybe<VideoInfo>& aVideo,
                                  nsISerialEventTarget* aManagerThread);
diff --git a/gfx/thebes/DeviceManagerDx.cpp b/gfx/thebes/DeviceManagerDx.cpp
index d7ae97659a4f..57fada77891d 100644
--- a/gfx/thebes/DeviceManagerDx.cpp
+++ b/gfx/thebes/DeviceManagerDx.cpp
@@ -76,8 +76,11 @@ DeviceManagerDx::DeviceManagerDx()
   mFeatureLevels.AppendElement(D3D_FEATURE_LEVEL_11_0);
   mFeatureLevels.AppendElement(D3D_FEATURE_LEVEL_10_1);
   mFeatureLevels.AppendElement(D3D_FEATURE_LEVEL_10_0);
+  MOZ_COUNT_CTOR(DeviceManagerDx);
 }
 
+DeviceManagerDx::~DeviceManagerDx() { MOZ_COUNT_DTOR(DeviceManagerDx); }
+
 bool DeviceManagerDx::LoadD3D11() {
   FeatureState& d3d11 = gfxConfig::GetFeature(Feature::D3D11_COMPOSITING);
   MOZ_ASSERT(d3d11.IsEnabled());
diff --git a/gfx/thebes/DeviceManagerDx.h b/gfx/thebes/DeviceManagerDx.h
index 766624d729ce..18e9a71eb7e7 100644
--- a/gfx/thebes/DeviceManagerDx.h
+++ b/gfx/thebes/DeviceManagerDx.h
@@ -52,6 +52,7 @@ class DeviceManagerDx final {
   static void Shutdown();
 
   DeviceManagerDx();
+  ~DeviceManagerDx();
 
   static DeviceManagerDx* Get() { return sInstance; }