Build config: use_atk only if glib is enabled

Also, disable glib explicitly for headless.

Change-Id: I10c4d46e623b9a5b563067e51ba9daf1646369a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2075084Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744786}

build/args/headless.gn

@@ -42,3 +42,4 @@ use_pulseaudio = false
 use_udev = false
 rtc_use_pipewire = false
 v8_enable_lazy_source_positions = false
+use_glib = false

build/config/ui.gni

@@ -48,7 +48,7 @@ use_x11 = is_linux && !use_ozone
 assert(!use_glib || (is_linux && !is_chromeos && !is_chromecast))
 
 # Whether to use atk, the Accessibility ToolKit library
-use_atk = is_desktop_linux && !is_chromecast
+use_atk = is_desktop_linux && !is_chromecast && use_glib
 # =============================================
 #   PLEASE DO NOT ADD MORE FLAGS TO THIS FILE
 # =============================================