Enable Vulkan support by default

Currently, building with Vulkan support is behind a gn flag
(enable_vulkan). It would be easy to not build & test with this flag. As
a result, it would also be easy to allow Vulkan support to bitrot.

Enabling Vulkan building by default would keep the Vulkan code
buildable. This patch does that.

(You still need a command line parameter of --enable-vulkan when running
Chrome to actually use the Vulkan codepath. This is just for the
building.)

BUG=848100

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I26fa03f9f6e2dc924691db913f723661b510f272
Reviewed-on: https://chromium-review.googlesource.com/1098117Reviewed-by: Brian Salomon <bsalomon@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Chris Blume <cblume@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567307}

gpu/vulkan/BUILD.gn

@@ -14,60 +14,57 @@ buildflag_header("buildflags") {
 }
 
 if (enable_vulkan) {
-  vulkan_lib_dir = getenv("VULKAN_SDK") + "/lib"
   component("vulkan") {
     output_name = "vulkan_wrapper"
 
-    if (is_linux) {
-      sources = [
-        "vulkan_command_buffer.cc",
-        "vulkan_command_buffer.h",
-        "vulkan_command_pool.cc",
-        "vulkan_command_pool.h",
-        "vulkan_descriptor_layout.cc",
-        "vulkan_descriptor_layout.h",
-        "vulkan_descriptor_pool.cc",
-        "vulkan_descriptor_pool.h",
-        "vulkan_descriptor_set.cc",
-        "vulkan_descriptor_set.h",
-        "vulkan_device_queue.cc",
-        "vulkan_device_queue.h",
-        "vulkan_export.h",
-        "vulkan_function_pointers.cc",
-        "vulkan_function_pointers.h",
-        "vulkan_image_view.cc",
-        "vulkan_image_view.h",
-        "vulkan_implementation.cc",
-        "vulkan_implementation.h",
-        "vulkan_instance.cc",
-        "vulkan_instance.h",
-        "vulkan_render_pass.cc",
-        "vulkan_render_pass.h",
-        "vulkan_sampler.cc",
-        "vulkan_sampler.h",
-        "vulkan_shader_module.cc",
-        "vulkan_shader_module.h",
-        "vulkan_surface.cc",
-        "vulkan_surface.h",
-        "vulkan_swap_chain.cc",
-        "vulkan_swap_chain.h",
-      ]
+    sources = [
+      "vulkan_command_buffer.cc",
+      "vulkan_command_buffer.h",
+      "vulkan_command_pool.cc",
+      "vulkan_command_pool.h",
+      "vulkan_descriptor_layout.cc",
+      "vulkan_descriptor_layout.h",
+      "vulkan_descriptor_pool.cc",
+      "vulkan_descriptor_pool.h",
+      "vulkan_descriptor_set.cc",
+      "vulkan_descriptor_set.h",
+      "vulkan_device_queue.cc",
+      "vulkan_device_queue.h",
+      "vulkan_export.h",
+      "vulkan_function_pointers.cc",
+      "vulkan_function_pointers.h",
+      "vulkan_image_view.cc",
+      "vulkan_image_view.h",
+      "vulkan_implementation.cc",
+      "vulkan_implementation.h",
+      "vulkan_instance.cc",
+      "vulkan_instance.h",
+      "vulkan_render_pass.cc",
+      "vulkan_render_pass.h",
+      "vulkan_sampler.cc",
+      "vulkan_sampler.h",
+      "vulkan_shader_module.cc",
+      "vulkan_shader_module.h",
+      "vulkan_surface.cc",
+      "vulkan_surface.h",
+      "vulkan_swap_chain.cc",
+      "vulkan_swap_chain.h",
+    ]
 
-      configs += [ "//build/config:precompiled_headers" ]
+    configs += [ "//build/config:precompiled_headers" ]
 
-      defines = [ "VULKAN_IMPLEMENTATION" ]
+    defines = [ "VULKAN_IMPLEMENTATION" ]
 
-      if (use_x11) {
-        defines += [ "VK_USE_PLATFORM_XLIB_KHR" ]
-      }
+    if (use_x11) {
+      defines += [ "VK_USE_PLATFORM_XLIB_KHR" ]
+    }
 
-      all_dependent_configs = [ "//third_party/vulkan:vulkan_config" ]
+    all_dependent_configs = [ "//third_party/vulkan:vulkan_config" ]
 
-      deps = [
-        "//base",
-        "//ui/gfx",
-      ]
-    }
+    deps = [
+      "//base",
+      "//ui/gfx",
+    ]
   }
 
   test("vulkan_tests") {
@@ -79,15 +76,6 @@ if (enable_vulkan) {
       "tests/vulkan_tests_main.cc",
     ]
 
-    if (current_cpu == "x64") {
-      lib_dirs = [
-        "/usr/lib/x86_64-linux-gnu",
-        vulkan_lib_dir,
-      ]
-    } else {
-      assert(false, "Unsupported vulkan target: " + current_cpu)
-    }
-
     deps = [
       "//base/test:test_support",
       "//gpu/vulkan/init",

gpu/vulkan/features.gni

@@ -2,9 +2,11 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/ui.gni")
+
 # Features used by targets inside and outside of |gpu/vulkan|.
 # For details see declare_args() in build/config/BUILDCONFIG.gn.
 declare_args() {
   # Enable experimental vulkan backend.
-  enable_vulkan = false
+  enable_vulkan = is_linux && use_x11
 }

skia/BUILD.gn

@@ -23,9 +23,6 @@ skia_support_pdf = !is_ios && enable_basic_printing
 
 declare_args() {
   skia_whitelist_serialized_typefaces = false
-  if (enable_vulkan) {
-    vulkan_sdk_path = getenv("VULKAN_SDK")
-  }
 }
 
 # External-facing config for dependent code.
@@ -49,7 +46,7 @@ config("skia_config") {
   ]
   if (enable_vulkan) {
     include_dirs += [
-      "$vulkan_sdk_path/include",
+      "//third_party/vulkan/include",
       "//third_party/skia/third_party/vulkanmemoryallocator",
     ]
     configs = [ "//third_party/vulkan:vulkan_config" ]

third_party/vulkan/BUILD.gn

@@ -5,15 +5,4 @@
 config("vulkan_config") {
   defines = [ "VK_NO_PROTOTYPES" ]
   include_dirs = [ "include" ]
-  vulkan_lib_dir = getenv("VULKAN_SDK") + "/lib"
-  libs = [ "vulkan" ]
-
-  if (current_cpu == "x64") {
-    lib_dirs = [
-      "/usr/lib/x86_64-linux-gnu",
-      vulkan_lib_dir,
-    ]
-  } else {
-    assert(false, "Unsupported vulkan target: " + current_cpu)
-  }
 }