Improve scroll performance on Windows 10 with high precision touchpads.

ui/views/win/hwnd_message_handler.h

Index: ui/views/win/hwnd_message_handler.h
diff --git a/ui/views/win/hwnd_message_handler.h b/ui/views/win/hwnd_message_handler.h
index 79374fd3d0f9ca3605432dd47522ccffe1be39c5..e7fc8af7b518ae3ba83bfa765a5fdbed2d1f9bd7 100644
--- a/ui/views/win/hwnd_message_handler.h
+++ b/ui/views/win/hwnd_message_handler.h
@@ -30,7 +30,10 @@ namespace gfx {
 class Canvas;
 class ImageSkia;
 class Insets;
-}
+namespace win {
+class DirectManipulationHelper;
+}  // namespace win
+}  // namespace gfx
 
 namespace ui  {
 class ViewProp;
@@ -593,6 +596,11 @@ class VIEWS_EXPORT HWNDMessageHandler :
   // The factory used with BEGIN_SAFE_MSG_MAP_EX.
   base::WeakPtrFactory<HWNDMessageHandler> weak_factory_;
 
+  // This class provides functionality to register the legacy window as a
+  // Direct Manipulation consumer. This allows us to support smooth scroll
+  // in Chrome on Windows 10.
+  scoped_ptr<gfx::win::DirectManipulationHelper> direct_manipulation_helper_;
+
   DISALLOW_COPY_AND_ASSIGN(HWNDMessageHandler);
 };