Scaling scroll/fling events in multi-monitor setup

ui/base/events/event.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/base/events/event.h"
 
 #if defined(USE_X11)
 #include <X11/Xlib.h>
 #endif
 
@@ skipping 597 matching lines @@
                          const gfx::Point& location,
                          int flags,
                          float x_offset,
                          float y_offset)
     : MouseEvent(type, location, location, flags),
       x_offset_(x_offset),
       y_offset_(y_offset) {
   CHECK(IsScrollEvent());
 }
 
+void ScrollEvent::Scale(const float factor) {
+  x_offset_ *= factor;
+  y_offset_ *= factor;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // GestureEvent
 
 GestureEvent::GestureEvent(EventType type,
                            int x,
                            int y,
                            int flags,
                            base::TimeDelta time_stamp,
                            const GestureEventDetails& details,
                            unsigned int touch_ids_bitfield)
     : LocatedEvent(type, gfx::Point(x, y), gfx::Point(x, y), time_stamp, flags),
       details_(details),
       touch_ids_bitfield_(touch_ids_bitfield) {
 }
 
 GestureEvent::~GestureEvent() {
 }
 
 int GestureEvent::GetLowestTouchId() const {
   if (touch_ids_bitfield_ == 0)
     return -1;
   int i = -1;
   // Find the index of the least significant 1 bit
   while (!(1 << ++i & touch_ids_bitfield_));
   return i;
 }
 
 }  // namespace ui