GN: Wayland build overrides

Introduce //build_overrides/wayland.gni to simplify the management of
the wayland dependencies.

Bug: chromium:1327041, angleproject:7409
Change-Id: I24cd7c0aa1025acbfe681afb07ccb384ff52bb62

BUILD.gn

@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build_overrides/wayland.gni")
+
 # import the ozone_platform_x11 variable
 import("gni/angle.gni")
 if (angle_enable_vulkan) {
@@ -1034,7 +1036,7 @@ angle_source_set("angle_gl_enum_utils") {
 
 if (angle_use_wayland) {
   config("angle_wayland_config") {
-    if (!defined(use_system_libwayland) || use_system_libwayland) {
+    if (use_system_libwayland) {
       libs = [
         "wayland-client",
         "wayland-egl",
@@ -1042,23 +1044,19 @@ if (angle_use_wayland) {
     }
 
     include_dirs = [
-      "$angle_wayland_dir/egl",
-      "$angle_wayland_dir/src",
-
-      # In case we are building with chromium, we need to take into account the case
-      # where wayland-egl-backend.h is not installed in the system include directories
-      "//third_party/wayland/src/egl",
+      "$wayland_dir/egl",
+      "$wayland_dir/src",
     ]
   }
 
   group("angle_wayland") {
     public_configs = [ ":angle_wayland_config" ]
 
-    if (defined(use_system_libwayland) && !use_system_libwayland) {
-      # Use chromium third-party targets
+    if (!use_system_libwayland) {
+      # Use third-party targets
       public_deps = [
-        "//third_party/wayland:wayland_client",
-        "//third_party/wayland:wayland_egl",
+        "$wayland_gn_dir:wayland_client",
+        "$wayland_gn_dir:wayland_egl",
       ]
     }
   }

build_overrides/wayland.gni

+# Copyright 2022 The ANGLE Project Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//gni/angle.gni")
+
+# Path to Wayland sources
+wayland_dir = angle_wayland_dir
+
+# ANGLE standalone has no Wayland GN
+wayland_gn_dir = ""
+
+use_system_libwayland = true

src/common/vulkan/BUILD.gn

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build_overrides/swiftshader.gni")
+import("//build_overrides/wayland.gni")
 import("../../../gni/angle.gni")
 
 declare_args() {
@@ -30,7 +31,7 @@ if (angle_enable_vulkan || angle_build_vulkan_system_info) {
       defines = [ "ANGLE_SHARED_LIBVULKAN=1" ]
     }
     if (angle_use_wayland) {
-      include_dirs = [ "$angle_wayland_dir/src" ]
+      include_dirs = [ "$wayland_dir/src" ]
     }
     configs = [ "$angle_root:angle_vulkan_wayland_config" ]
   }

src/third_party/volk/BUILD.gn

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build_overrides/wayland.gni")
 import("../../../gni/angle.gni")
 
 config("volk_config") {
@@ -17,6 +18,6 @@ source_set("volk") {
   configs += [ "$angle_root:angle_no_cfi_icall" ]
   public_deps = [ "$angle_vulkan_headers_dir:vulkan_headers" ]
   if (angle_use_wayland) {
-    include_dirs = [ "$angle_wayland_dir/src" ]
+    include_dirs = [ "$wayland_dir/src" ]
   }
 }