Migrate ui::Transform to gfx::Transform

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index f9fcbc9208246dbb3eb655747676951ea4f70368..f446e22f7f9b1dc199211510c4240b34ee0d84fe 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -297,7 +297,7 @@ class COMPOSITOR_EXPORT Layer
   // Following are invoked from the animation or if no animation exists to
   // update the values immediately.
   void SetBoundsImmediately(const gfx::Rect& bounds);
-  void SetTransformImmediately(const ui::Transform& transform);
+  void SetTransformImmediately(const gfx::Transform& transform);
   void SetOpacityImmediately(float opacity);
   void SetVisibilityImmediately(bool visibility);
   void SetBrightnessImmediately(float brightness);
@@ -337,7 +337,7 @@ class COMPOSITOR_EXPORT Layer
   // This layer's children, in bottom-to-top stacking order.
   std::vector<Layer*> children_;
 
-  ui::Transform transform_;
+  gfx::Transform transform_;
 
   gfx::Rect bounds_;