Move visual rect unioning between paired items to cc::DisplayItemList.

ui/compositor/paint_cache.cc

Index: ui/compositor/paint_cache.cc
diff --git a/ui/compositor/paint_cache.cc b/ui/compositor/paint_cache.cc
index ba3855ad307fac2b1edcac03ea986b6cad4e36c7..9feaca05e832d1e3b253bbb9f7deb004b31655e9 100644
--- a/ui/compositor/paint_cache.cc
+++ b/ui/compositor/paint_cache.cc
@@ -21,8 +21,8 @@ bool PaintCache::UseCache(const PaintContext& context,
     return false;
   DCHECK(context.list_);
   gfx::Rect bounds_in_layer = context.ToLayerSpaceBounds(size_in_context);
-  context.list_->CreateAndAppendItem<cc::DrawingDisplayItem>(bounds_in_layer,
-                                                             display_item_);
+  context.list_->CreateAndAppendDrawingItem<cc::DrawingDisplayItem>(
+      bounds_in_layer, display_item_);
   return true;
 }