--- a/gfx/thebes/gfxQuartzNativeDrawing.cpp
+++ b/gfx/thebes/gfxQuartzNativeDrawing.cpp
@@ -19,17 +19,18 @@ gfxQuartzNativeDrawing::gfxQuartzNativeD
 }
 
 CGContextRef
 gfxQuartzNativeDrawing::BeginNativeDrawing()
 {
   NS_ASSERTION(!mCGContext, "BeginNativeDrawing called when drawing already in progress");
 
   DrawTarget *dt = mDrawTarget;
-  if (dt->IsDualDrawTarget() || dt->IsTiledDrawTarget()) {
+  if (dt->IsDualDrawTarget() || dt->IsTiledDrawTarget() ||
+      dt->GetBackendType() != BackendType::SKIA) {
     // We need a DrawTarget that we can get a CGContextRef from:
     Matrix transform = dt->GetTransform();
 
     mNativeRect = transform.TransformBounds(mNativeRect);
     mNativeRect.RoundOut();
     // Quartz theme drawing often adjusts drawing rects, so make
     // sure our surface is big enough for that.
     mNativeRect.Inflate(5);
@@ -44,16 +45,17 @@ gfxQuartzNativeDrawing::BeginNativeDrawi
 
     if (mTempDrawTarget) {
         transform.PostTranslate(-mNativeRect.x, -mNativeRect.y);
         mTempDrawTarget->SetTransform(transform);
     }
     dt = mTempDrawTarget;
   }
   if (dt) {
+    MOZ_ASSERT(dt->GetBackendType() == BackendType::SKIA);
     mCGContext = mBorrowedContext.Init(dt);
     MOZ_ASSERT(mCGContext);
   }
   return mCGContext;
 }
 
 void
 gfxQuartzNativeDrawing::EndNativeDrawing()