Create BUILD.gn files for //media/filters.

media/base/mac/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.
 
 assert(is_mac || is_ios)
 
 source_set("mac") {
   # Note: This source_set is depended on only by //media. In the component
   # build, if other component targets also depend on it, multiple copies of
   # the ObjC classes declared in the files below will cause warnings at
   # run-time.
-  visibility = [ "//media" ]
+  visibility = [
+    "//media",
+    "//media/filters",
+  ]
 
   set_sources_assignment_filter([])
   sources = [
     "video_frame_mac.cc",
     "video_frame_mac.h",
     "videotoolbox_helpers.cc",
     "videotoolbox_helpers.h",
   ]
   if (is_mac) {
     libs = [
@@ skipping 20 matching lines @@
   sources = [
     "video_frame_mac_unittests.cc",
   ]
   libs = [ "CoreVideo.framework" ]
   configs += [ "//media:media_config" ]
   deps = [
     "//testing/gtest",
     "//ui/gfx:color_space",
   ]
 }