Improve scroll performance on Windows 10 with high precision touchpads.

content/browser/renderer_host/legacy_render_widget_host_win.h

Index: content/browser/renderer_host/legacy_render_widget_host_win.h
diff --git a/content/browser/renderer_host/legacy_render_widget_host_win.h b/content/browser/renderer_host/legacy_render_widget_host_win.h
index 70f685939fd9139889060ff442afe8044f340ada..0980508ed9f167d8d1c53aedb17ae9382faa415e 100644
--- a/content/browser/renderer_host/legacy_render_widget_host_win.h
+++ b/content/browser/renderer_host/legacy_render_widget_host_win.h
@@ -11,10 +11,17 @@
 #include <oleacc.h>
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/win/scoped_comptr.h"
 #include "content/common/content_export.h"
 #include "ui/gfx/geometry/rect.h"
 
+namespace gfx {
+namespace win {
+class DirectManipulationHelper;
+}  // namespace win
+}  // namespace gfx
+
 namespace ui {
 class WindowEventTarget;
 }
@@ -143,6 +150,11 @@ class CONTENT_EXPORT LegacyRenderWidgetHostHWND
 
   RenderWidgetHostViewAura* host_;
 
+  // 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(LegacyRenderWidgetHostHWND);
 };