exo: Replace fling cancel with generic zero distance scroll

components/exo/wayland/server.cc

 // Copyright 2015 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 "components/exo/wayland/server.h"
 
 #include <grp.h>
 #include <linux/input.h>
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 2094 matching lines @@
     double x_value = offset.x() * kAxisStepDistance;
     wl_pointer_send_axis(pointer_resource_, TimeTicksToMilliseconds(time_stamp),
                          WL_POINTER_AXIS_HORIZONTAL_SCROLL,
                          wl_fixed_from_double(-x_value));
 
     double y_value = offset.y() * kAxisStepDistance;
     wl_pointer_send_axis(pointer_resource_, TimeTicksToMilliseconds(time_stamp),
                          WL_POINTER_AXIS_VERTICAL_SCROLL,
                          wl_fixed_from_double(-y_value));
   }
-  void OnPointerScrollCancel(base::TimeTicks time_stamp) override {
-    // Wayland doesn't know the concept of a canceling kinetic scrolling.
-    // But we can send a 0 distance scroll to emulate this behavior.
-    OnPointerScroll(time_stamp, gfx::Vector2dF(0, 0), false);
-    OnPointerScrollStop(time_stamp);
-  }
   void OnPointerScrollStop(base::TimeTicks time_stamp) override {
     if (wl_resource_get_version(pointer_resource_) >=
         WL_POINTER_AXIS_STOP_SINCE_VERSION) {
       wl_pointer_send_axis_stop(pointer_resource_,
                                 TimeTicksToMilliseconds(time_stamp),
                                 WL_POINTER_AXIS_HORIZONTAL_SCROLL);
       wl_pointer_send_axis_stop(pointer_resource_,
                                 TimeTicksToMilliseconds(time_stamp),
                                 WL_POINTER_AXIS_VERTICAL_SCROLL);
     }
@@ skipping 941 matching lines @@
   DCHECK(event_loop);
   wl_event_loop_dispatch(event_loop, timeout.InMilliseconds());
 }
 
 void Server::Flush() {
   wl_display_flush_clients(wl_display_.get());
 }
 
 }  // namespace wayland
 }  // namespace exo