Reland "Move gn setup for vulkan library/headers into their own third_party directory."

This reverts commit 2c2a119f945eedaced4bf081347a53f05cf0c39c.

Reason for revert: Relanding with fixes

Original change's description:
> Revert "Move gn setup for vulkan library/headers into their own third_party directory."
> 
> This reverts commit 477094250cd55a38d4d796ab6c50eb57bdba65e1.
> 
> Reason for revert:
> I think we know this broke the MoltenVK bots.  It also appears to have broken the Fuchsia roll: https://logs.chromium.org/v/?s=fuchsia%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8945885190914943680%2F%2B%2Fsteps%2Fbuild%2F0%2Fsteps%2Fbuild_fuchsia%2F0%2Fsteps%2Fgn_gen%2F0%2Fstdout
> 
> Original change's description:
> > Move gn setup for vulkan library/headers into their own third_party directory.
> > 
> > Bug: skia:
> > Change-Id: I4605f0d962271efb77bf3c17f1b0daaaddfb51c8
> > Reviewed-on: https://skia-review.googlesource.com/128540
> > Commit-Queue: Greg Daniel <egdaniel@google.com>
> > Reviewed-by: Mike Klein <mtklein@google.com>
> > Reviewed-by: Ben Wagner <bungeman@google.com>
> 
> TBR=egdaniel@google.com,mtklein@google.com,bungeman@google.com
> 
> Change-Id: I6e41d98e39883eff34424a2f352b0c8adec178db
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:
> Reviewed-on: https://skia-review.googlesource.com/129444
> Reviewed-by: Mike Klein <mtklein@google.com>
> Commit-Queue: Mike Klein <mtklein@google.com>

Bug: skia:
Change-Id: I26b4b1f7196dd1bd8bf2e7641ef741c90c742c81
Reviewed-on: https://skia-review.googlesource.com/129445
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/third_party/vulkan/BUILD.gn b/third_party/vulkan/BUILD.gn
new file mode 100644
index 0000000000..425ccdabcb
--- /dev/null
+++ b/third_party/vulkan/BUILD.gn
@@ -0,0 +1,69 @@
+# Copyright 2018 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+if (is_fuchsia) {
+  import("//build/vulkan/config.gni")
+}
+
+declare_args() {
+  skia_vulkan_header = ""
+  skia_tools_vulkan_header_dir = ""
+
+  # When buliding on Android we get the header via the NDK so no need for any extra path.
+  if (is_fuchsia) {
+    skia_tools_vulkan_header_dir = "$fuchsia_vulkan_sdk/include"
+  } else if (is_linux || is_win) {
+    skia_tools_vulkan_header_dir = "$skia_vulkan_sdk/include"
+  }
+}
+
+config("moltenvk") {
+  if (is_ios) {
+    moltenvk_framework_path = "$skia_moltenvk_path/MoltenVK/iOS"
+  } else {
+    moltenvk_framework_path = "$skia_moltenvk_path/MoltenVK/macOS"
+  }
+  cflags = [
+    "-F$moltenvk_framework_path",
+    "-isystem$skia_moltenvk_path/MoltenVK/include",  # for <vulkan/vulkan.h>
+  ]
+  ldflags = [ "-F$moltenvk_framework_path" ]
+  libs = [
+    "MoltenVK.framework",
+    "Metal.framework",
+    "IOSurface.framework",
+    "QuartzCore.framework",
+    "Foundation.framework",
+  ]
+  if (is_ios) {
+    libs += [ "UIKit.framework" ]
+  } else {
+    libs += [ "IOKit.framework" ]
+  }
+  defines = [ "SK_MOLTENVK" ]
+}
+
+config("vulkan_config") {
+  include_dirs = []
+  configs = []
+
+  if (skia_tools_vulkan_header_dir != "") {
+    include_dirs += [ skia_tools_vulkan_header_dir ]
+  }
+  defines = [ "SK_VULKAN" ]
+  if (skia_vulkan_header != "") {
+    defines += [ "SK_VULKAN_HEADER=\"$skia_vulkan_header\"" ]
+  } else if (defined(is_skia_standalone) && is_skia_standalone &&
+             !is_official_build) {
+    defines += [ "SK_VULKAN_HEADER=\"GrVulkanDefines.h\"" ]
+  }
+  if (skia_moltenvk_path != "") {
+    configs += [ ":moltenvk" ]
+  }
+}
+
+source_set("vulkan") {
+  public_configs = [ ":vulkan_config" ]
+}