GN: Make X11 optional, based on a user-defined variable.

Not all Linux platforms will have X11 available (Wayland, GGP), so we have to
declare a variable that checks use_x11 separately.

Bug: angleproject:4116
Change-Id: I7e33956da6344b8db4d4e32dbbd1b42f58f7019c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1919632
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

AUTHORS

@@ -60,3 +60,4 @@ Till Rathmann
 Nick Shaforostov
 Jaime Bernardo
 Le Hoang Quyen
+Ethan Lee

BUILD.gn

@@ -20,7 +20,7 @@ if (angle_has_build) {
 declare_args() {
   # Use the PCI lib to collect GPU information on Linux.
   use_libpci = is_linux && (!is_chromecast || is_cast_desktop_build) &&
-               (use_x11 || use_ozone)
+               (angle_use_x11 || use_ozone)
 
   # Link in system libGL, to work with apitrace.  See doc/DebuggingTips.md.
   angle_link_glx = false
@@ -380,7 +380,7 @@ angle_static_library("angle_gpu_info_util") {
   if (is_linux || is_fuchsia) {
     sources += libangle_gpu_info_util_linux_sources
 
-    if (use_x11) {
+    if (angle_use_x11) {
       sources += libangle_gpu_info_util_x11_sources
       deps += [ "src/third_party/libXNVCtrl:libXNVCtrl" ]
       defines += [ "GPU_INFO_USE_X11" ]
@@ -582,7 +582,7 @@ config("libANGLE_config") {
     }
   }
 
-  if (use_x11) {
+  if (angle_use_x11) {
     defines += [ "ANGLE_USE_X11" ]
   }
 }
@@ -689,7 +689,7 @@ angle_source_set("libANGLE_base") {
     if (is_win) {
       sources += libangle_gl_wgl_sources
     }
-    if (use_x11) {
+    if (angle_use_x11) {
       sources += libangle_gl_glx_sources
       deps += [ "src/third_party/libXNVCtrl:libXNVCtrl" ]
       libs += [
@@ -1062,7 +1062,7 @@ angle_source_set("angle_util_loader") {
 
 config("angle_util_config") {
   include_dirs = [ "." ]
-  if (is_linux && use_x11) {
+  if (is_linux && angle_use_x11) {
     libs = [ "X11" ]
   }
 }
@@ -1112,7 +1112,7 @@ foreach(is_shared_library,
       ]
     }
 
-    if (use_x11) {
+    if (angle_use_x11) {
       sources += util_x11_sources
     }
 

build_overrides/vulkan_headers.gni

@@ -0,0 +1,7 @@
+# Copyright 2019 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")
+
+vulkan_use_x11 = angle_use_x11

gni/angle.gni

@@ -21,6 +21,8 @@ if (angle_has_build) {
   if (is_win) {
     import("//build/config/win/visual_studio_version.gni")
   }
+
+  angle_use_x11 = use_x11 && !is_ggp
 } else {
   declare_args() {
     is_ubsan = false
@@ -28,7 +30,7 @@ if (angle_has_build) {
     is_asan = false
     build_with_chromium = false
     dcheck_always_on = false
-    use_x11 = is_linux
+    angle_use_x11 = is_linux && !is_ggp
     use_ozone = false
     use_fuzzing_engine = false
   }
@@ -84,16 +86,17 @@ declare_args() {
   angle_enable_d3d9 = is_win && !angle_is_winuwp
   angle_enable_d3d11 = is_win
   angle_enable_gl =
-      (ozone_platform_gbm || !is_linux || (use_x11 && !is_chromeos)) &&
-      !is_fuchsia && !angle_is_winuwp
+      (ozone_platform_gbm || !is_linux || (angle_use_x11 && !is_chromeos)) &&
+      !is_fuchsia && !angle_is_winuwp && !is_ggp
 
   # ANGLE Vulkan backend on Android requires API level 26, i.e. Oreo, due to
   # Vulkan Validation Layers compatibility issues, see http://crrev/c/1405714.
   # Otherwise, API level 24 would have been enough.
   angle_enable_vulkan =
       angle_has_build &&
-      ((is_win && !angle_is_winuwp) || (is_linux && use_x11 && !is_chromeos) ||
-       (is_android && ndk_api_level_at_least_26) || is_fuchsia)
+      ((is_win && !angle_is_winuwp) ||
+       (is_linux && angle_use_x11 && !is_chromeos) ||
+       (is_android && ndk_api_level_at_least_26) || is_fuchsia || is_ggp)
   angle_enable_null = true
   angle_enable_essl = true
   angle_enable_glsl = true

src/libANGLE/renderer/vulkan/BUILD.gn

@@ -19,7 +19,7 @@ declare_args() {
   # Currently SwiftShader's Vulkan front-end doesn't build on Android.
   # SwiftShader is not needed on Fuchsia because Vulkan is supported on all
   # devices that run Fuchsia.
-  angle_swiftshader = !is_android && !is_fuchsia
+  angle_swiftshader = !is_android && !is_fuchsia && !is_ggp
 }
 
 _vulkan_backend_sources = [
@@ -119,7 +119,7 @@ if (is_win) {
   ]
 }
 
-if (is_linux) {
+if (angle_use_x11) {
   _vulkan_backend_sources += [
     "xcb/DisplayVkXcb.cpp",
     "xcb/DisplayVkXcb.h",

src/tests/BUILD.gn

@@ -131,7 +131,7 @@ if (is_win || is_linux || is_mac || is_android || is_fuchsia) {
     if (is_win) {
       sources += angle_end2end_tests_win_sources
     }
-    if (use_x11) {
+    if (angle_use_x11) {
       sources += angle_end2end_tests_x11_sources
     }
     if (angle_enable_vulkan) {