Revert "ozone: Build with xkbcommon by default on is_linux && !is_chromecast"

This reverts commit 713420fb.

Reason for revert: Causes MSAN failure
More details in crbug/1027853

Original change's description:
> ozone: Build with xkbcommon by default on is_linux && !is_chromecast
> 
> This is necessary on Linux targets unless you don't want keyboard
> support or only need support for a hardcoded US layout.
> 
> Noticed because the CQ broke after building for ozone locally. This
> reduces the number of flags needed to build as the Linux Ozone builder
> does.
> 
> Bug: 1026476
> 
> Change-Id: I77352c133b1f7552301b6e1f252d40a4f2c72106
> 
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1925370
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Kevin Schoedel <kpschoedel@chromium.org>
> Commit-Queue: Michael Spang <spang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#718240}

TBR=sky@chromium.org,spang@chromium.org,kpschoedel@chromium.org

Change-Id: I4fa0de1881acbf1eaf7e70bfe4b24dbc84647f43
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1026476
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1932436Reviewed-by: Tim Schumann <tschumann@chromium.org>
Commit-Queue: Tim Schumann <tschumann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718445}

ui/base/ui_features.gni

@@ -6,7 +6,7 @@ import("//build/config/ui.gni")
 
 declare_args() {
   # Optional system library.
-  use_xkbcommon = use_ozone && is_linux && !is_chromecast
+  use_xkbcommon = false
 
   # Whether the platform provides a native accessibility toolkit.
   has_native_accessibility = use_atk || is_win || is_mac