Add build_overrides/vulkan_memory_allocator.gni

After https://chromium-review.googlesource.com/c/external/github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator/+/2804453
the VulkanMemoryAllocator dependency will start including this config
file to get the position of the vulkan-headers.

Also factor common vulkan variables to vulkan_common.gni like is done
in Chromium.

Bug: tint:700
Bug: chromium:1195554

Change-Id: Idbb8b957c17b2cbdbd518c13706d02ef4d74e93f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/46862
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

build_overrides/vulkan_common.gni

@@ -0,0 +1,19 @@
+# Copyright 2021 The Dawn Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+vulkan_headers_dir = "//third_party/vulkan-deps/vulkan-headers/src"
+
+# Subdirectories for generated files
+vulkan_data_subdir = "vulkandata"
+vulkan_gen_subdir = ""

build_overrides/vulkan_loader.gni

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-vulkan_headers_dir = "//third_party/vulkan-deps/vulkan-headers/src"
+import("//build_overrides/vulkan_common.gni")
 
-vulkan_gen_subdir = "vulkan_loader"
 vulkan_loader_shared = true

build_overrides/vulkan_memory_allocator.gni

@@ -0,0 +1,15 @@
+# Copyright 2021 The Dawn Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build_overrides/vulkan_common.gni")

build_overrides/vulkan_tools.gni

@@ -1,8 +1,15 @@
-# 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.
+# Copyright 2021 The Dawn Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
-vulkan_headers_dir = "//third_party/vulkan-deps/vulkan-headers/src"
-
-vulkan_data_subdir = "vulkandata"
-vulkan_gen_subdir = "angle/vulkan"
+import("//build_overrides/vulkan_common.gni")

build_overrides/vulkan_validation_layers.gni

@@ -12,17 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import("//build_overrides/vulkan_common.gni")
+
 # These are variables that are overridable by projects that include Dawn.
 # The values in this file are the defaults for when we are building from
 # Dawn's repository.
-vulkan_headers_dir = "//third_party/vulkan-deps/vulkan-headers/src"
 vvl_spirv_tools_dir = "//third_party/vulkan-deps/spirv-tools/src"
 vvl_glslang_dir = "//third_party/vulkan-deps/glslang/src"
 
-# Subdirectories for generated files
-vulkan_data_subdir = "vulkandata"
-vulkan_gen_subdir = ""
-
 # Fake the use_x11 when inside Dawn's repository
 import("../scripts/dawn_features.gni")
 use_x11 = dawn_use_x11