Enable media in default GN build.

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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 20 matching lines @@
     "//chrome/utility",
     "//components:all_components",
     "//content",
     "//crypto",
     "//extensions/common/api:extensions_api",
     "//device/usb",
     "//gin",
     "//gpu",
     "//google_apis",
     "//ipc",
+    "//media",
     "//mojo",
     "//mojo/common",
     "//mojo/environment:chromium",
     "//mojo/service_manager",
     "//mojo/system",
     "//net",
     "//pdf",
     "//ppapi:ppapi_c",
     "//printing",
     "//sandbox",
@@ skipping 132 matching lines @@
     ]
   }
 
   if (use_ozone) {
     deps += [
       "//ui/events/ozone:events_ozone",
       "//ui/events/ozone:events_ozone_evdev",
     ]
   }
 }