Specifically UIControlsDesktopX11 is the place I'm referring to.

+marcheu@

GetCursorScreenPoint should be using the last mouse position, which should be updated by these events. IIRC, the implementation has changed from XQueryPointer because it's synchronous call to X11, which is slow and can cause dead lock (I don't remember if we actually had dead lock though).

DesktopScreenX11::GetCursorScreenPoint() uses XQueryPointer and has for at least the past 4 years.

Even longer than 4 years since ScreenGtk::GetCursorScreenPoint() used to call gtk_display_get_cursor() which called XQueryPointer().

Ok it could have been done only for chromeos (linux views). It was pre aura, so it was more than 5 years ago.

If you switch to XWarpPointer, one thing you may have to do is to keep windows used in the test within the display (X root window). I had a problem with multi display tests in the past, which uses XWarpPointer to move the cursor to another WTH but it failed because it was trying to move the cursor to outside of the root window. It's probably not an issue in most of desktop tests, but just in case.

One thing to note is if we use XWarpPointer, we may get additional mouse-move etc. events from the server, which may or may not break some tests, maybe.

sky@ Which tab dragging tests are affected?

There is a bunch. https://codereview.chromium.org/2277923002/ turns on one test. It's only chromeos and windows at this time as the linux non-chromeos is broke because of this bug.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/49530a1b55b7b3b6d1210d2dfdb6d8b075a1116d

commit 49530a1b55b7b3b6d1210d2dfdb6d8b075a1116d
Author: sky <sky@chromium.org>
Date: Wed Aug 24 23:37:46 2016

Attempt 2 at enabling a tab dragging test

This was reverted because of flake on linux. I've identified why the
flake was happening and filed a bug, so I'm leaving the enabling as
only chromeos and windows at this time.

These tests were disabled because the resize lock can trigger at
random points, blocking event delivery and breaking the tests. I've
added a switch to disable the resize lock so that events now have
known delivery order.

BUG= 331924 ,  640741 
TEST=none
R=oshima@chromium.org

Review-Url: https://codereview.chromium.org/2277923002
Cr-Commit-Position: refs/heads/master@{#414198}

[modify] https://crrev.com/49530a1b55b7b3b6d1210d2dfdb6d8b075a1116d/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
[modify] https://crrev.com/49530a1b55b7b3b6d1210d2dfdb6d8b075a1116d/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4dcd8ad19534e6084fff6bc2229acd90ecf4c316

commit 4dcd8ad19534e6084fff6bc2229acd90ecf4c316
Author: thomasanderson <thomasanderson@google.com>
Date: Mon Sep 12 18:30:56 2016

X11: Add TestDesktopScreenX11 to simulate mouse movement in ui tests

BUG= 640741 

Review-Url: https://codereview.chromium.org/2327623002
Cr-Commit-Position: refs/heads/master@{#417978}

[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/chrome/browser/ui/views/chrome_browser_main_extra_parts_views.cc
[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/chrome/test/base/in_process_browser_test.cc
[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/chrome/test/base/view_event_test_platform_part_default.cc
[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/ui/views/BUILD.gn
[add] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/ui/views/test/test_desktop_screen_x11.cc
[add] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/ui/views/test/test_desktop_screen_x11.h
[modify] https://crrev.com/4dcd8ad19534e6084fff6bc2229acd90ecf4c316/ui/views/test/ui_controls_factory_desktop_aurax11.cc