Remove some global UI defines

build/config/ui.gni

Index: build/config/ui.gni
diff --git a/build/config/ui.gni b/build/config/ui.gni
index 1212ad2cc8b495e46e781ebe0ef784a735645a32..0f78dd9f0b5418dd1fc7213802bbfb033ad480cd 100644
--- a/build/config/ui.gni
+++ b/build/config/ui.gni
@@ -54,9 +54,6 @@ declare_args() {
 
   # Enable experimental vulkan backend.
   enable_vulkan = false
-
-  # Allow aura to access x11 clipboard.
-  enable_clipboard_aurax11 = false
 }
 
 # Additional dependent variables -----------------------------------------------
@@ -67,8 +64,6 @@ declare_args() {
 # with the Aura window manager.
 ui_compositor_image_transport = use_aura && is_linux
 
-use_default_render_theme = use_aura && !is_android
-
 # Indicates if the UI toolkit depends on X11.
 use_x11 = is_linux && !use_ozone
 
@@ -87,9 +82,6 @@ if (is_linux && !use_ozone) {
 
 # Whether to use atk, the Accessibility ToolKit library
 use_atk = is_desktop_linux && use_x11
-
-use_clipboard_aurax11 =
-    (is_desktop_linux && use_aura && use_x11) || enable_clipboard_aurax11
 # =============================================
 #   PLEASE DO NOT ADD MORE FLAGS TO THIS FILE
 # =============================================