Implemented smooth scrolling using xinput2 in X11.

ui/aura/window_tree_host_x11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/window_tree_host_x11.h"
 
 #include <strings.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/extensions/Xrandr.h>
@@ skipping 329 matching lines @@
           next_event.xmotion.subwindow == xev->xmotion.subwindow &&
           next_event.xmotion.state == xev->xmotion.state) {
         XNextEvent(xev->xany.display, &last_event);
         xev = &last_event;
       } else {
         break;
       }
     }
   }
 
+  if (xev->type == EnterNotify || xev->type == LeaveNotify) {
+    // Clear stored scroll data
+    ui::DeviceDataManagerX11::GetInstance()->InvalidateScrollClasses();
+  }

[sadrul, 2015/01/30 15:49:15]

Can you move this into X11EventSource::DispatchEvent() instead?

+
   if ((xev->type == EnterNotify || xev->type == LeaveNotify) &&
       xev->xcrossing.detail == NotifyInferior) {
     // Ignore EventNotify and LeaveNotify  events from children of |xwindow_|.
     // NativeViewGLSurfaceGLX adds a child to |xwindow_|.
     // TODO(pkotwicz|tdanderson): Figure out whether the suppression is
     // necessary. crbug.com/385716
     return ui::POST_DISPATCH_STOP_PROPAGATION;
   }
 
   if (xev->type == EnterNotify ||
@@ skipping 367 matching lines @@
 }
 
 namespace test {
 
 void SetUseOverrideRedirectWindowByDefault(bool override_redirect) {
   default_override_redirect = override_redirect;
 }
 
 }  // namespace test
 }  // namespace aura