Make dawn_use_x11 = use_x11 when building inside Chromium

The variable use_x11 in Chromium takes into account more thinks like
whether we are building in LaCrOS mode and more. If we don't do this,
compilation of Chromium fails when Dawn tries to include X11/Xlib.h

Bug: chromium:976495
Change-Id: I8b4e865f50f60235466c8ba72683927124aa094e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/30220
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

scripts/dawn_features.gni

diff --git a/scripts/dawn_features.gni b/scripts/dawn_features.gni
index 6f4f01e..09db849 100644
--- a/scripts/dawn_features.gni
+++ b/scripts/dawn_features.gni
@@ -16,6 +16,14 @@
 
 if (build_with_chromium) {
   import("//build/config/sanitizers/sanitizers.gni")
+  import("//build/config/ui.gni")
+
+  dawn_use_x11 = use_x11
+} else {
+  declare_args() {
+    # Whether Dawn should enable X11 support.
+    dawn_use_x11 = is_linux && !is_chromeos
+  }
 }
 
 declare_args() {
@@ -66,9 +74,6 @@
   dawn_enable_error_injection =
       is_debug || (build_with_chromium && use_fuzzing_engine)
 
-  # Whether Dawn should enable X11 support.
-  dawn_use_x11 = is_linux && !is_chromeos
-
   # Enable support WGSL for shaders.
   # Turned off for Skia, because Tint is currently not part of its DEPS.
   dawn_enable_wgsl = !defined(is_skia_standalone)