Bug 1232852 (part 1) - Set |aSnap| in two GetOpaqueRegion() overloadings that are missing it. r=roc.

--HG--
extra : rebase_source : f565bfee7883283847bf7ba6af68aaeb06e9fea3

layout/base/nsDisplayList.cpp

@@ -3220,6 +3220,8 @@ nsRegion
 nsDisplayBackgroundColor::GetOpaqueRegion(nsDisplayListBuilder* aBuilder,
                                           bool* aSnap)
 {
+  *aSnap = false;
+
   if (mColor.a != 1) {
     return nsRegion();
   }

layout/generic/nsImageFrame.cpp

@@ -1637,6 +1637,7 @@ nsDisplayImage::GetLayerState(nsDisplayListBuilder* aBuilder,
 nsDisplayImage::GetOpaqueRegion(nsDisplayListBuilder* aBuilder,
                                 bool* aSnap)
 {
+  *aSnap = false;
   if (mImage && mImage->IsOpaque()) {
     const nsRect frameContentBox = GetBounds(aSnap);
     return GetDestRect().Intersect(frameContentBox);