Chromecast: adds fake libffmpegsumo target for more graceful internal build.

chromecast/media/media.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
     'chromecast_branding%': 'Chromium',
     'libcast_media_gyp%': '',
     'use_default_libcast_media%': 1,
   },
   'targets': [
+    # TODO(gunsch): delete this target once Chromecast M44/earlier is obsolete.
+    # See: b/21639416
+    {
+      'target_name': 'libffmpegsumo',
+      'type': 'loadable_module',
+      'sources': ['empty.cc'],
+    },
     {
       'target_name': 'media_base',
       'type': '<(component)',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../crypto/crypto.gyp:crypto',
         '../../third_party/widevine/cdm/widevine_cdm.gyp:widevine_cdm_version_h',
         '<(libcast_media_gyp):libcast_media_1.0',
       ],
       'sources': [
@@ skipping 285 matching lines @@
             '../..',
           ],
           'sources': [
             'base/cast_media_default.cc',
           ],
         }
       ]
     }],
   ],
 }