diff --git a/gfx/layers/Layers.cpp b/gfx/layers/Layers.cpp
index 8d6ec2b7bfad..42f7de5ff3d4 100644
--- a/gfx/layers/Layers.cpp
+++ b/gfx/layers/Layers.cpp
@@ -1466,7 +1466,11 @@ ContainerLayer::DefaultComputeEffectiveTransforms(const Matrix4x4& aTransformToS
     ComputeEffectiveTransformsForChildren(idealTransform);
   }
 
-  ComputeEffectiveTransformForMaskLayers(aTransformToSurface);
+  if (idealTransform.CanDraw2D()) {
+    ComputeEffectiveTransformForMaskLayers(aTransformToSurface);
+  } else {
+    ComputeEffectiveTransformForMaskLayers(Matrix4x4());
+  }
 }
 
 void
diff --git a/gfx/layers/basic/BasicCompositor.cpp b/gfx/layers/basic/BasicCompositor.cpp
index 12433ea33211..8a069478d0aa 100644
--- a/gfx/layers/basic/BasicCompositor.cpp
+++ b/gfx/layers/basic/BasicCompositor.cpp
@@ -397,25 +397,6 @@ RoundOut(Rect r)
   return IntRect(r.x, r.y, r.width, r.height);
 }
 
-static void
-SetupMask(const EffectChain& aEffectChain,
-          DrawTarget* aDest,
-          const IntPoint& aOffset,
-          RefPtr<SourceSurface>& aMaskSurface,
-          Matrix& aMaskTransform)
-{
-  if (aEffectChain.mSecondaryEffects[EffectTypes::MASK]) {
-    EffectMask *effectMask = static_cast<EffectMask*>(aEffectChain.mSecondaryEffects[EffectTypes::MASK].get());
-    aMaskSurface = effectMask->mMaskTexture->AsSourceBasic()->GetSurface(aDest);
-    if (!aMaskSurface) {
-      gfxWarning() << "Invalid sourceMask effect";
-    }
-    MOZ_ASSERT(effectMask->mMaskTransform.Is2D(), "How did we end up with a 3D transform here?!");
-    aMaskTransform = effectMask->mMaskTransform.As2D();
-    aMaskTransform.PostTranslate(-aOffset.x, -aOffset.y);
-  }
-}
-
 void
 BasicCompositor::DrawQuad(const gfx::Rect& aRect,
                           const gfx::Rect& aClipRect,
@@ -461,8 +442,7 @@ BasicCompositor::DrawQuad(const gfx::Rect& aRect,
 
     // When we apply the 3D transformation, we do it against a temporary
     // surface, so undo the coordinate offset.
-    new3DTransform = aTransform;
-    new3DTransform.PreTranslate(aRect.x, aRect.y, 0);
+    new3DTransform = Matrix4x4::Translation(aRect.x, aRect.y, 0) * aTransform;
   }
 
   buffer->PushClipRect(aClipRect);
@@ -472,8 +452,16 @@ BasicCompositor::DrawQuad(const gfx::Rect& aRect,
 
   RefPtr<SourceSurface> sourceMask;
   Matrix maskTransform;
-  if (aTransform.Is2D()) {
-    SetupMask(aEffectChain, dest, offset, sourceMask, maskTransform);
+  if (aEffectChain.mSecondaryEffects[EffectTypes::MASK]) {
+    EffectMask *effectMask = static_cast<EffectMask*>(aEffectChain.mSecondaryEffects[EffectTypes::MASK].get());
+    sourceMask = effectMask->mMaskTexture->AsSourceBasic()->GetSurface(dest);
+    if (!sourceMask) {
+      gfxWarning() << "Invalid sourceMask effect";
+    }
+    MOZ_ASSERT(effectMask->mMaskTransform.Is2D(), "How did we end up with a 3D transform here?!");
+    MOZ_ASSERT(!effectMask->mIs3D);
+    maskTransform = effectMask->mMaskTransform.As2D();
+    maskTransform.PostTranslate(-offset.x, -offset.y);
   }
 
   CompositionOp blendMode = CompositionOp::OP_OVER;
@@ -580,40 +568,8 @@ BasicCompositor::DrawQuad(const gfx::Rect& aRect,
 
     Transform(temp, source, new3DTransform, transformBounds.TopLeft());
 
-    SetupMask(aEffectChain, buffer, offset, sourceMask, maskTransform);
-
-    // Adjust for the fact that our content now start at 0,0 instead
-    // of the top left of transformBounds.
     transformBounds.MoveTo(0, 0);
-    maskTransform.PostTranslate(-transformBounds.x, -transformBounds.y);
-
-    if (sourceMask) {
-      // Transform the source by it's normal transform, and then the inverse
-      // of the mask transform so that it's in the mask's untransformed
-      // coordinate space.
-      Matrix old = buffer->GetTransform();
-      Matrix sourceTransform = old;
-
-      Matrix inverseMask = maskTransform;
-      inverseMask.Invert();
-
-      sourceTransform *= inverseMask;
-
-      SurfacePattern source(temp, ExtendMode::CLAMP, sourceTransform);
-
-      buffer->PushClipRect(transformBounds);
-
-      // Mask in the untransformed coordinate space, and then transform
-      // by the mask transform to put the result back into destination
-      // coords.
-      buffer->SetTransform(maskTransform);
-      buffer->MaskSurface(source, sourceMask, Point(0, 0));
-      buffer->SetTransform(old);
-
-      buffer->PopClip();
-    } else {
-      buffer->DrawSurface(temp, transformBounds, transformBounds);
-    }
+    buffer->DrawSurface(temp, transformBounds, transformBounds);
   }
 
   buffer->PopClip();
diff --git a/layout/reftests/layers/mask-layer-transform-ref.html b/layout/reftests/layers/mask-layer-transform-ref.html
deleted file mode 100644
index 54cd38607f95..000000000000
--- a/layout/reftests/layers/mask-layer-transform-ref.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<html>
-<body>
-    <div style="position:relative; left: 400px; width: 200px; height: 200px; overflow:hidden; border-radius: 20px;">
-        <div style="width:200px; height:200px; background-color:red; transform: perspective(100px) rotateY(10deg)"></div>
-    </div>
-</body>
-</html>
-
diff --git a/layout/reftests/layers/mask-layer-transform.html b/layout/reftests/layers/mask-layer-transform.html
deleted file mode 100644
index 0a809c50bde9..000000000000
--- a/layout/reftests/layers/mask-layer-transform.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<html>
-<body>
-    <div style="width:200px; height: 200px; transform: translate(400px);">
-        <div style="width: 200px; height: 200px; overflow:hidden; border-radius: 20px;">
-            <div style="width:200px; height:200px; background-color:red; transform: perspective(100px) rotateY(10deg)"></div>
-        </div>
-  </div>
-</body>
-</html>
-
diff --git a/layout/reftests/layers/reftest.list b/layout/reftests/layers/reftest.list
index 397753ced6b4..fbeed320eac4 100644
--- a/layout/reftests/layers/reftest.list
+++ b/layout/reftests/layers/reftest.list
@@ -19,4 +19,3 @@ skip-if(!asyncPan) != pull-background-displayport-4.html about:blank # fails wit
 skip-if(!asyncPan) != pull-background-displayport-5.html about:blank
 skip-if(!asyncPan) != pull-background-displayport-6.html about:blank # fails with non-overlay scrollbars and event regions due to bug 1148515
 fuzzy(2,30150) == opacity-blending.html opacity-blending-ref.html
-fuzzy(1,5) == mask-layer-transform.html mask-layer-transform-ref.html