--- a/widget/windows/InProcessWinCompositorWidget.cpp
+++ b/widget/windows/InProcessWinCompositorWidget.cpp
@@ -61,21 +61,20 @@ InProcessWinCompositorWidget::InProcessW
   // mNotDeferEndRemoteDrawing is set on the main thread during init,
   // but is only accessed after on the compositor thread.
   mNotDeferEndRemoteDrawing =
       StaticPrefs::layers_offmainthreadcomposition_frame_rate() == 0 ||
       gfxPlatform::IsInLayoutAsapMode() || gfxPlatform::ForceSoftwareVsync();
 }
 
 void InProcessWinCompositorWidget::OnDestroyWindow() {
-  EnterPresentLock();
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
   MutexAutoLock lock(mTransparentSurfaceLock);
   mTransparentSurface = nullptr;
   mMemoryDC = nullptr;
-  LeavePresentLock();
 }
 
 bool InProcessWinCompositorWidget::OnWindowResize(
     const LayoutDeviceIntSize& aSize) {
   return true;
 }
 
 void InProcessWinCompositorWidget::OnWindowModeChange(nsSizeMode aSizeMode) {}
@@ -261,43 +260,42 @@ void InProcessWinCompositorWidget::Creat
   RefPtr<gfxWindowsSurface> surface =
       new gfxWindowsSurface(aSize, SurfaceFormat::A8R8G8B8_UINT32);
   mTransparentSurface = surface;
   mMemoryDC = surface->GetDC();
 }
 
 void InProcessWinCompositorWidget::UpdateTransparency(
     nsTransparencyMode aMode) {
-  EnterPresentLock();
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
   MutexAutoLock lock(mTransparentSurfaceLock);
   if (mTransparencyMode == aMode) {
     return;
   }
 
   mTransparencyMode = aMode;
   mTransparentSurface = nullptr;
   mMemoryDC = nullptr;
 
   if (mTransparencyMode == eTransparencyTransparent) {
     EnsureTransparentSurface();
   }
-  LeavePresentLock();
 }
 
 bool InProcessWinCompositorWidget::HasGlass() const {
   MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread() ||
              wr::RenderThread::IsInRenderThread());
 
   nsTransparencyMode transparencyMode = mTransparencyMode;
   return transparencyMode == eTransparencyGlass ||
          transparencyMode == eTransparencyBorderlessGlass;
 }
 
 void InProcessWinCompositorWidget::ClearTransparentWindow() {
-  EnterPresentLock();
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
   MutexAutoLock lock(mTransparentSurfaceLock);
   if (!mTransparentSurface) {
     return;
   }
 
   EnsureTransparentSurface();
 
   IntSize size = mTransparentSurface->GetSize();
@@ -305,17 +303,16 @@ void InProcessWinCompositorWidget::Clear
     RefPtr<DrawTarget> drawTarget =
         gfxPlatform::CreateDrawTargetForSurface(mTransparentSurface, size);
     if (!drawTarget) {
       return;
     }
     drawTarget->ClearRect(Rect(0, 0, size.width, size.height));
     RedrawTransparentWindow();
   }
-  LeavePresentLock();
 }
 
 bool InProcessWinCompositorWidget::RedrawTransparentWindow() {
   MOZ_ASSERT(mTransparencyMode == eTransparencyTransparent);
 
   LayoutDeviceIntSize size = GetClientSize();
 
   ::GdiFlush();