add video hole support to the gn build

BUG=329447

Review URL: https://codereview.chromium.org/1042543003

Cr-Original-Commit-Position: refs/heads/master@{#323201}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e6a9adc346e41d6c7676689174c12fe15ff5dbe1

config/BUILD.gn

@@ -228,6 +228,9 @@ config("feature_flags") {
   if (enable_pre_sync_backup) {
     defines += [ "ENABLE_PRE_SYNC_BACKUP" ]
   }
+  if (enable_video_hole) {
+    defines += [ "VIDEO_HOLE=1" ]
+  }
 }
 
 # Debug/release ----------------------------------------------------------------

config/features.gni

@@ -74,6 +74,9 @@ declare_args() {
   enable_one_click_signin = is_win || is_mac || (is_linux && !is_chromeos)
 
   enable_remoting = !is_ios && !is_android
+
+  # Enable hole punching for the protected video.
+  enable_video_hole = is_android
 }
 
 # Additional dependent variables -----------------------------------------------