Add GN rules for forwarder2 and chromium_commands

build/android/pylib/device/commands/commands.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.
 
 {
   'targets': [
     {
+      # GN version: //build/android/pylib/devices/commands:chromium_commands
       'target_name': 'chromium_commands',
       'type': 'none',
       'variables': {
         'add_to_dependents_classpaths': 0,
         'java_in_dir': ['java'],
       },
       'includes': [
         '../../../../../build/java.gypi',
       ],
     }
   ],
 }