GN: Get //chrome/* mostly working on android

components/gcm_driver.gypi

 # 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: //components/gcm_driver
       'target_name': 'gcm_driver',
       'type': 'static_library',
@@ skipping 127 matching lines @@
             # TODO(johnme): Fix the layering violation of depending on content/
             '../content/content.gyp:content_java',
             '../sync/sync.gyp:sync_java',
           ],
           'variables': {
             'java_in_dir': 'gcm_driver/android/java',
           },
           'includes': [ '../build/java.gypi' ],
         },
         {
+          # GN version: //components/gcm_driver:jni_headers
           'target_name': 'gcm_driver_jni_headers',
           'type': 'none',
           'sources': [
             'gcm_driver/android/java/src/org/chromium/components/gcm_driver/GCMDriver.java',
           ],
           'variables': {
             'jni_gen_package': 'components/gcm_driver',
           },
           'includes': [ '../build/jni_generator.gypi' ],
         },
       ],
      },
     ],
   ],
 }