[1] has introduced two dependencies on //modules/desktop_capture:pipewire_config even when rtc_use_pipewire=false, this CL changes the guard in order to make sure GN doesn't raise errors when is_linux=true and rtc_use_pipewire=false. [1] - https://webrtc-review.googlesource.com/c/src/+/160649 No-Try: True Bug: chromium:682122 Change-Id: I28d2f10936dd75199a2a98862751708eb1e5615a Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/187122 Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Tommi <tommi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#32345}