gn: Fix more build issues on Win

gpu/command_buffer/service/BUILD.gn

 # Copyright 2014 The Chromium 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("//build/config/ui.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 source_set("service") {
   sources = [
     "async_pixel_transfer_delegate.cc",
@@ skipping 98 matching lines @@
     "vertex_attrib_manager.h",
     "vertex_attrib_manager.cc",
   ]
 
   defines = [ "GPU_IMPLEMENTATION" ]
 
   configs += [
     "//third_party/khronos:khronos_headers",
   ]
 
+  # Prefer mesa GL headers to system headers, which cause problems on Win.
+  include_dirs = [ "//third_party/mesa/src/include" ]
+
   public_deps = [
     "//gpu/command_buffer/common",
   ]
   deps = [
     ":disk_cache_proto",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//crypto",
     "//third_party/angle:translator",
     "//third_party/protobuf:protobuf_lite",
     "//third_party/re2",
     "//third_party/smhasher:cityhash",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 
   if (ui_compositor_image_transport) {
-    include_dirs = [ "//third_party/khronos" ]
+    include_dirs += [ "//third_party/khronos" ]
   }
 
   if (is_win || is_android || (is_linux && use_x11)) {
     sources += [
       "async_pixel_transfer_manager_egl.cc",
       "async_pixel_transfer_manager_egl.h",
     ]
   }
 
   if (is_android && !is_debug) {
     # On Android optimize more since this component can be a bottleneck.
     configs -= [ "//build/config/compiler:optimize" ]
     configs += [ "//build/config/compiler:optimize_max" ]
   }
 }
 
 proto_library("disk_cache_proto") {
   sources = [ "disk_cache_proto.proto" ]
 }