Ensure that trackpad and trackpoint scrolling works on Windows desktop Aura with legacy trackpad dr…

ui/views/widget/widget_hwnd_utils.cc

Index: ui/views/widget/widget_hwnd_utils.cc
===================================================================
--- ui/views/widget/widget_hwnd_utils.cc	(revision 243629)
+++ ui/views/widget/widget_hwnd_utils.cc	(working copy)
@@ -133,6 +133,18 @@
     default:
       NOTREACHED();
   }
+
+#if defined(USE_AURA)
+  // Certain trackpad drivers on Windows have bugs where in they don't generate
+  // WM_MOUSEWHEEL messages for the trackpoint and trackpad scrolling gestures
+  // unless there is an entry for Chrome with the class name of the Window.
+  // These drivers check if the window under the trackpoint has the WS_VSCROLL/
+  // WS_HSCROLL style and if yes they generate the legacy WM_VSCROLL/WM_HSCROLL
+  // messages. We add these styles to ensure that trackpad/trackpoint scrolling
+  // work.
+  if (!params.child)
+    *style |= WS_VSCROLL | WS_HSCROLL;
+#endif
 }
 
 }  // namespace