Short term workaround to deal with calculation error caused by inverted matrix.

ui/aura/test/event_generator.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/test/event_generator.h"
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop_proxy.h"
 #include "ui/aura/client/screen_position_client.h"
@@ skipping 138 matching lines @@
 
   gfx::Vector2dF diff(point - current_location_);
   for (float i = 1; i <= count; i++) {
     gfx::Vector2dF step(diff);
     step.Scale(i / count);
     gfx::Point move_point = current_location_ + gfx::ToRoundedVector2d(step);
     if (!grab_)
       UpdateCurrentRootWindow(move_point);
     ConvertPointToTarget(current_root_window_, &move_point);
     ui::MouseEvent mouseev(event_type, move_point, move_point, flags_);
+    mouseev.set_system_location(move_point);
     Dispatch(&mouseev);
   }
   current_location_ = point;
 }
 
 void EventGenerator::MoveMouseRelativeTo(const Window* window,
                                          const gfx::Point& point_in_parent) {
   gfx::Point point(point_in_parent);
   ConvertPointFromTarget(window, &point);
   MoveMouseTo(point);
@@ skipping 365 matching lines @@
     base::MessageLoopProxy::current()->PostTask(
         FROM_HERE,
         base::Bind(&EventGenerator::DispatchNextPendingEvent,
                    base::Unretained(this)));
   }
 }
 
 
 }  // namespace test
 }  // namespace aura