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..f67319e68d21f0cc2a60530789384cdeeba6646a 100644
--- a/ui/views/win/hwnd_message_handler.h
+++ b/ui/views/win/hwnd_message_handler.h
@@ -23,6 +23,7 @@
 #include "ui/events/event.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/sequential_id_generator.h"
+#include "ui/gfx/win/direct_manipulation.h"

[sky, 2015/08/11 23:45:02]

forward declare the class and include in the .cc.

[ananta, 2015/08/12 00:41:58]

Done.

 #include "ui/gfx/win/window_impl.h"
 #include "ui/views/views_export.h"
 
@@ -593,6 +594,11 @@ 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);
 };