cros: Change look of partial magnifier.

ash/magnifier/partial_magnification_controller.h

Index: ash/magnifier/partial_magnification_controller.h
diff --git a/ash/magnifier/partial_magnification_controller.h b/ash/magnifier/partial_magnification_controller.h
index b42f61df9c4baebe423c849ffe27b49e81b1a04b..146f672517457a44a33b4b09a3eed21966e82e77 100644
--- a/ash/magnifier/partial_magnification_controller.h
+++ b/ash/magnifier/partial_magnification_controller.h
@@ -86,9 +86,9 @@ class ASH_EXPORT PartialMagnificationController : public ui::EventHandler,
   // Draws an outline that is overlayed on top of |zoom_layer_|.
   std::unique_ptr<ui::Layer> border_layer_;
   // Draws a multicolored black/white/black border on top of |border_layer_|.
-  // This must be ordered after |border_layer_| so that it gets destroyed after
-  // |border_layer_|, otherwise |border_layer_| will have a pointer to a deleted
-  // delegate.
+  // Also draws a shadow around the border. This must be ordered after
+  // |border_layer_| so that it gets destroyed after |border_layer_|, otherwise
+  // |border_layer_| will have a pointer to a deleted delegate.
   std::unique_ptr<BorderRenderer> border_renderer_;
   // Masks the content of |zoom_layer_| so that only a circle is magnified.
   std::unique_ptr<ContentMask> zoom_mask_;