Mark the ET_MOUSE_MOVED created from a pointer grab as synthesized.

ui/views/widget/desktop_aura/desktop_window_tree_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/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 1900 matching lines @@
   switch (xev->type) {
     case EnterNotify:
     case LeaveNotify: {
       OnCrossingEvent(xev->type == EnterNotify, xev->xcrossing.focus,
                       xev->xcrossing.mode, xev->xcrossing.detail);
 
       // Ignore EventNotify and LeaveNotify events from children of |xwindow_|.
       // NativeViewGLSurfaceGLX adds a child to |xwindow_|.
       if (xev->xcrossing.detail != NotifyInferior) {
         ui::MouseEvent mouse_event(xev);
+        // EnterNotify creates ET_MOUSE_MOVED. Mark as synthesized as this is
+        // not a real mouse move event.
+        if (xev->type == EnterNotify)
+          mouse_event.set_flags(mouse_event.flags() | ui::EF_IS_SYNTHESIZED);

[sadrul, 2017/06/16 16:03:36]

Looks like we are always doing this [1, 2]. Can we instead update [3] so we
don't need to explicitly do this?

[1]
https://cs.chromium.org/chromium/src/ui/platform_window/x11/x11_window.cc?l=94
[2]
https://cs.chromium.org/chromium/src/ui/events/platform/x11/x11_event_source_...
[3] https://cs.chromium.org/chromium/src/ui/events/x/events_x_utils.cc?l=478

[Kevin McNee, 2017/06/29 22:41:42]

Done.

         DispatchMouseEvent(&mouse_event);
       }
       break;
     }
     case Expose: {
       gfx::Rect damage_rect_in_pixels(xev->xexpose.x, xev->xexpose.y,
                                       xev->xexpose.width, xev->xexpose.height);
       compositor()->ScheduleRedrawRect(damage_rect_in_pixels);
       break;
     }
@@ skipping 349 matching lines @@
 
 // static
 DesktopWindowTreeHost* DesktopWindowTreeHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopWindowTreeHostX11(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views