UpdateMonitors() crops the selected RANDR monitor to the root window,
in case X returns a monitor that lies outside it. But it wasn't enough.
SelectSource() alters the selection directly and doesn't call
UpdateMonitors(), so it also needs to crop. This fixes the case
where a virtual monitor is added, the screen resolution is reduced,
then the new monitor is selected (which now extends outside the reduced
screen size).
This CL also fixes an issue where the ScreenCapturerHelper would
sometimes expand a damage-region outside the DesktopFrame boundary.
This occurred because the helper's size was set to the full
pixel-buffer, so it didn't crop correctly to the monitor's rect.
This CL sets the helper's correct size, and removes some unnecessary
cropping now that the helper will do it correctly.
Bug: chromium:1266179
Change-Id: I8eb8f3302701be4f393934c0899f41def3512853
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/237120
Commit-Queue: Joe Downing <joedow@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#35304}
b75d01690f