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..8ecefe21322c13c84cd9dd884aa1aec5b0e3f433 100644
--- a/content/browser/renderer_host/legacy_render_widget_host_win.h
+++ b/content/browser/renderer_host/legacy_render_widget_host_win.h
@@ -11,6 +11,7 @@
 #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"
@@ -20,6 +21,7 @@ class WindowEventTarget;
 }
 
 namespace content {
+class DirectManipulationHelper;
 class RenderWidgetHostViewAura;
 
 // Reasons for the existence of this class outlined below:-
@@ -143,6 +145,11 @@ 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<DirectManipulationHelper> direct_manipulation_helper_;
+
   DISALLOW_COPY_AND_ASSIGN(LegacyRenderWidgetHostHWND);
 };