Mark mouse events created for Enter/Leave notify as synthesized as they're not real mouse events.

ui/aura/root_window_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/root_window_host_x11.h"
 
 #include <strings.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/Xfixes.h>
 #include <X11/extensions/XInput2.h>
@@ skipping 443 matching lines @@
 bool RootWindowHostX11::Dispatch(const base::NativeEvent& event) {
   XEvent* xev = event;
 
   if (FindEventTarget(event) == x_root_window_)
     return DispatchEventForRootWindow(event);
 
   switch (xev->type) {
     case EnterNotify:
     case LeaveNotify: {
       ui::MouseEvent mouse_event(xev);
+      // Mark as synthesized as this is not real mouse event.
+      mouse_event.set_flags(mouse_event.flags() | ui::EF_IS_SYNTHESIZED);

[sky, 2013/08/06 21:11:05]

This seems like a real event to me. Why the synthesized? Is the bug that on
showing we should ignore and not here?

[sadrul, 2013/08/06 21:18:51]

My understanding is the EF_IS_SYNTHESIZED is set here since the Enter/Leave
events are system-generated events (by x11) as opposed to user-generated Motion
etc. events

[oshima, 2013/08/06 21:20:32]

This creates mouse MOVE event, even though mouse doesn't move,
hence synthesized. (MOVE event is generated separately when a mouse
enters by move)
Right now, I've seen this only in test bots so far, although
this can happen in real device. I can file if you want. let me know.

[sky, 2013/08/06 21:37:47]

Then should the synthesized be on the move and not this?

       TranslateAndDispatchMouseEvent(&mouse_event);
       break;
     }
     case Expose: {
       gfx::Rect damage_rect(xev->xexpose.x, xev->xexpose.y,
                             xev->xexpose.width, xev->xexpose.height);
       delegate_->AsRootWindow()->ScheduleRedrawRect(damage_rect);
       break;
     }
     case KeyPress: {
@@ skipping 665 matching lines @@
 }
 
 namespace test {
 
 void SetUseOverrideRedirectWindowByDefault(bool override_redirect) {
   default_override_redirect = override_redirect;
 }
 
 }  // namespace test
 }  // namespace aura