Preliminary atomic patch

ui/ozone/platform/drm/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/linux/pkg_config.gni")
 import("//ui/ozone/ozone.gni")
 
 declare_args() {
   use_mesa_platform_null = false
+  ozone_use_atomic = false
 }
 
 pkg_config("libdrm") {
   packages = [ "libdrm" ]
 }
 
 source_set("drm_common") {
   sources = [
     "drm_surface_factory.cc",
     "drm_surface_factory.h",
@@ skipping 53 matching lines @@
     "host/drm_native_display_delegate.cc",
     "host/drm_native_display_delegate.h",
     "host/drm_window_host.cc",
     "host/drm_window_host.h",
     "host/drm_window_host_manager.cc",
     "host/drm_window_host_manager.h",
   ]
 
   defines = [ "OZONE_IMPLEMENTATION" ]
 
+  if (ozone_use_atomic) {
+    defines += [ "OZONE_USE_ATOMIC" ]
+    sources += [
+      "gpu/hardware_display_plane_atomic.cc",
+      "gpu/hardware_display_plane_atomic.h",
+      "gpu/hardware_display_plane_manager_atomic.cc",
+      "gpu/hardware_display_plane_manager_atomic.h",
+    ]
+  }
+
   deps = [
     "//base",
     "//skia",
     "//ipc",
     "//ui/base",
     "//ui/display/types",
     "//ui/display/util",
     "//ui/events",
     "//ui/events/devices",
     "//ui/events/ozone:events_ozone_evdev",
@@ skipping 75 matching lines @@
       "//ui/events/ozone:events_ozone_layout",
     ]
 
     public_configs = [ ":libgbm" ]
 
     if (use_mesa_platform_null) {
       defines += [ "USE_MESA_PLATFORM_NULL" ]
     }
   }
 }