Add --enable-seccomp-filter-sandbox to about:flags on Android.

content/content_renderer.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
     '../cc/cc.gyp:cc',
     '../cc/blink/cc_blink.gyp:cc_blink',
@@ skipping 804 matching lines @@
       ],
     }],
     ['enable_browser_cdms==1', {
       'sources': [
         'renderer/media/crypto/proxy_media_keys.cc',
         'renderer/media/crypto/proxy_media_keys.h',
         'renderer/media/crypto/renderer_cdm_manager.cc',
         'renderer/media/crypto/renderer_cdm_manager.h',
       ],
     }],
+    ['use_seccomp_bpf==1', {
+      'defines': ['USE_SECCOMP_BPF'],
+    }],
   ],
   'target_conditions': [
     ['OS=="android"', {
       'sources/': [
         ['include', '^renderer/render_view_linux\\.cc$'],
       ],
     }],
   ],
 }