add video hole support to the gn build

build/config/BUILD.gn

 # Copyright (c) 2013 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/allocator.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/module_args/v8.gni")
 
@@ skipping 210 matching lines @@
   }
   if (v8_use_external_startup_data) {
     defines += [ "V8_USE_EXTERNAL_STARTUP_DATA" ]
   }
   if (enable_background) {
     defines += [ "ENABLE_BACKGROUND=1" ]
   }
   if (enable_pre_sync_backup) {
     defines += [ "ENABLE_PRE_SYNC_BACKUP" ]
   }
+  if (enable_video_hole) {
+    defines += [ "VIDEO_HOLE=1" ]
+  }
 }
 
 # Debug/release ----------------------------------------------------------------
 
 config("debug") {
   defines = [
     "_DEBUG",
     "DYNAMIC_ANNOTATIONS_ENABLED=1",
     "WTF_USE_DYNAMIC_ANNOTATIONS=1",
   ]
@@ skipping 87 matching lines @@
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
       "Foundation.framework",
       "UIKit.framework",
     ]
   } else if (is_linux) {
     libs = [ "dl" ]
   }
 }