Migrate ui::Transform to gfx::Transform

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 361a39904a2b58b9cc1862fe805fc7e5802ccd1c..d4dda66d728b1133d14e44b68c140c2b4ea96009 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -1044,7 +1044,7 @@ bool Widget::OnNativeWidgetPaintAccelerated(const gfx::Rect& dirty_region) {
   // to avoid leaving ghosts.
   bool force_clear = false;
   if (GetRootView()->layer()) {
-    const ui::Transform& layer_transform = GetRootView()->layer()->transform();
+    const gfx::Transform& layer_transform = GetRootView()->layer()->transform();
     if (layer_transform != GetRootView()->GetTransform()) {
       // The layer has not caught up to the view (i.e., the layer is still
       // animating), and so a clear is required.