--- a/gfx/layers/Layers.cpp
+++ b/gfx/layers/Layers.cpp
@@ -330,19 +330,24 @@ Layer::CalculateScissorRect(const nsIntR
     return nsIntRect(currentClip.TopLeft(), nsIntSize(0, 0));
   }
 
   nsIntRect scissor = *clipRect;
   if (!container->UseIntermediateSurface()) {
     gfxMatrix matrix;
     DebugOnly<bool> is2D = container->GetEffectiveTransform().Is2D(&matrix);
     // See DefaultComputeEffectiveTransforms below
-    NS_ASSERTION(is2D && !matrix.HasNonIntegerTranslation(),
-                 "Non-integer-translation transform with clipped child should have forced intermediate surface");
-    scissor.MoveBy(nsIntPoint(PRInt32(matrix.x0), PRInt32(matrix.y0)));
+    NS_ASSERTION(is2D && matrix.PreservesAxisAlignedRectangles(),
+                 "Non preserves axis aligned transform with clipped child should have forced intermediate surface");
+    gfxRect r(scissor.x, scissor.y, scissor.width, scissor.height);
+    gfxRect trScissor = matrix.TransformBounds(r);
+    trScissor.Round();
+    if (!gfxUtils::GfxRectToIntRect(trScissor, &scissor)) {
+      return nsIntRect(currentClip.TopLeft(), nsIntSize(0, 0));
+    }
 
     // Find the nearest ancestor with an intermediate surface
     do {
       container = container->GetParent();
     } while (container && !container->UseIntermediateSurface());
   }
   if (container) {
     scissor.MoveBy(-container->GetIntermediateSurfaceRect().TopLeft());
@@ -403,17 +408,21 @@ ContainerLayer::DefaultComputeEffectiveT
   PRBool useIntermediateSurface;
   float opacity = GetEffectiveOpacity();
   if (opacity != 1.0f && HasMultipleChildren()) {
     useIntermediateSurface = PR_TRUE;
   } else {
     useIntermediateSurface = PR_FALSE;
     gfxMatrix contTransform;
     if (!mEffectiveTransform.Is2D(&contTransform) ||
+#ifdef MOZ_GFX_OPTIMIZE_MOBILE
+        !contTransform.PreservesAxisAlignedRectangles()) {
+#else
         contTransform.HasNonIntegerTranslation()) {
+#endif
       for (Layer* child = GetFirstChild(); child; child = child->GetNextSibling()) {
         const nsIntRect *clipRect = child->GetEffectiveClipRect();
         /* We can't (easily) forward our transform to children with a non-empty clip
          * rect since it would need to be adjusted for the transform. See
          * the calculations performed by CalculateScissorRect above.
          */
         if (clipRect && !clipRect->IsEmpty() && !child->GetVisibleRegion().IsEmpty()) {
           useIntermediateSurface = PR_TRUE;