[Window Capture] Inaccurate cursor position during window sharing on X11
[Window Capture] Inaccurate cursor position during window sharing on X11

{root_x, root_y} should be used to report the absolute cursor position in
MouseCursorMonitorX11.

Bug: chromium:778035
Change-Id: I421005d52786a57da8e8c3901bdf4afa2843ff24
Reviewed-on: https://webrtc-review.googlesource.com/15680
Reviewed-by: Jamie Walch <6969cd2a405898dc33bef14ddd3e152c3cd07803@chromium.org>
Commit-Queue: Zijie He <0175c16456617950f1607b27294c14b126a588d1@chromium.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#20432}
TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc