Change Aura overlay scrollbars from solid color to painted scrollbars.

cc/trees/layer_tree_settings.h

Index: cc/trees/layer_tree_settings.h
diff --git a/cc/trees/layer_tree_settings.h b/cc/trees/layer_tree_settings.h
index 22275d88e4ed32fd22e20135f0d1684d69f3fe25..7148e92e0dc6740f649cf98504e5fc2a7e17e53b 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -9,6 +9,7 @@
 
 #include <vector>
 
+#include "base/time/time.h"
 #include "cc/base/cc_export.h"
 #include "cc/debug/layer_tree_debug_state.h"
 #include "cc/output/managed_memory_policy.h"
@@ -56,9 +57,10 @@ class CC_EXPORT LayerTreeSettings {
     THINNING,
   };
   ScrollbarAnimator scrollbar_animator = NO_ANIMATOR;
-  int scrollbar_fade_delay_ms = 0;
-  int scrollbar_fade_resize_delay_ms = 0;
-  int scrollbar_fade_duration_ms = 0;
+  base::TimeDelta scrollbar_fade_delay;
+  base::TimeDelta scrollbar_fade_resize_delay;
+  base::TimeDelta scrollbar_fade_duration;
+  base::TimeDelta scrollbar_thinning_duration;
   SkColor solid_color_scrollbar_color = SK_ColorWHITE;
   bool timeout_and_draw_when_animation_checkerboards = true;
   bool layer_transforms_should_scale_layer_contents = false;