Pass gfx structs by const ref (gfx::Vector2d/F)

ui/events/ozone/evdev/device_event_dispatcher_evdev.h

 // 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.
 
 #ifndef UI_EVENTS_OZONE_EVDEV_DEVICE_EVENT_DISPATCHER_H_
 #define UI_EVENTS_OZONE_EVDEV_DEVICE_EVENT_DISPATCHER_H_
 
 #include <vector>
 
 #include "base/time/time.h"
@@ skipping 63 matching lines @@
   int device_id;
   gfx::PointF location;
   gfx::Vector2d delta;
   base::TimeDelta timestamp;
 };
 
 struct EVENTS_OZONE_EVDEV_EXPORT ScrollEventParams {
   ScrollEventParams(int device_id,
                     EventType type,
                     const gfx::PointF location,
-                    const gfx::Vector2dF delta,
-                    const gfx::Vector2dF ordinal_delta,
+                    const gfx::Vector2dF& delta,
+                    const gfx::Vector2dF& ordinal_delta,
                     int finger_count,
                     const base::TimeDelta timestamp);
   ScrollEventParams(const ScrollEventParams& other);
   ~ScrollEventParams();
 
   int device_id;
   EventType type;
   const gfx::PointF location;
   const gfx::Vector2dF delta;
   const gfx::Vector2dF ordinal_delta;
@@ skipping 43 matching lines @@
       const std::vector<TouchscreenDevice>& devices) = 0;
   virtual void DispatchMouseDevicesUpdated(
       const std::vector<InputDevice>& devices) = 0;
   virtual void DispatchTouchpadDevicesUpdated(
       const std::vector<InputDevice>& devices) = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_EVDEV_DEVICE_EVENT_DISPATCHER_H_