build: Remove `is_desktop_linux` GN arg

This is now defined the same as `is_linux` and is no longer needed.

Bug: 1132395
Change-Id: Ibbdc6666c52c38e4765d4792a7a10e0c1e8c6747
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2443496Reviewed-by: Dirk Pranke <dpranke@google.com>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816246}

build/config/BUILDCONFIG.gn

@@ -130,10 +130,6 @@ declare_args() {
   # separate flags.
   is_official_build = false
 
-  # Whether we're a traditional desktop unix.
-  # Deprecated: Please use `is_linux` instead. See https://crbug.com/1132395
-  is_desktop_linux = current_os == "linux"
-
   # Set to true when compiling with the Clang compiler.
   is_clang = current_os != "linux" ||
              (current_cpu != "s390x" && current_cpu != "s390" &&

chrome/test/BUILD.gn

@@ -3107,7 +3107,7 @@ if (!is_android) {
           [ "../browser/site_isolation/spellcheck_per_process_browsertest.cc" ]
     }
 
-    if (is_win || is_mac || (is_desktop_linux && !chromeos_is_browser_only)) {
+    if (is_win || is_mac || (is_linux && !chromeos_is_browser_only)) {
       sources +=
           [ "../browser/ui/views/profiles/profile_picker_view_browsertest.cc" ]
     }

third_party/wayland/features.gni

@@ -9,7 +9,7 @@ declare_args() {
   # Controls whether the build should use the version of Wayland
   # library shipped with the system or Chromium third_party.
   use_system_libwayland =
-      is_desktop_linux && !is_chromecast && !chromeos_is_browser_only &&
+      is_linux && !is_chromecast && !chromeos_is_browser_only &&
       default_toolchain != "//build/toolchain/cros:target"
 
   # Path to wayland-scanner. Has effect only when the system libwayland is used.

ui/views/BUILD.gn

@@ -1025,7 +1025,7 @@ source_set("test_support") {
     deps += [ "//ui/base/x" ]
   }
 
-  if (use_ozone && is_desktop_linux) {
+  if (use_ozone && is_linux) {
     sources += [
       "test/test_desktop_screen_ozone.cc",
       "test/test_desktop_screen_ozone.h",