Add support for calling the java Callback from native.

base/base.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.
 
 {
   'includes': [
     'trace_event/trace_event.gypi',
   ],
   'target_defaults': {
     'variables': {
@@ skipping 14 matching lines @@
           'android/apk_assets.cc',
           'android/apk_assets.h',
           'android/application_status_listener.cc',
           'android/application_status_listener.h',
           'android/base_jni_onload.cc',
           'android/base_jni_onload.h',
           'android/base_jni_registrar.cc',
           'android/base_jni_registrar.h',
           'android/build_info.cc',
           'android/build_info.h',
+          'android/callback_android.cc',
+          'android/callback_android.h',
           'android/command_line_android.cc',
           'android/command_line_android.h',
           'android/content_uri_utils.cc',
           'android/content_uri_utils.h',
           'android/context_utils.cc',
           'android/context_utils.h',
           'android/cpu_features.cc',
           'android/cxa_demangle_stub.cc',
           'android/event_log.cc',
           'android/event_log.h',
@@ skipping 1050 matching lines @@
           'i18n/time_formatting.h',
           'i18n/timezone.cc',
           'i18n/timezone.h',
           'i18n/utf8_validator_tables.cc',
           'i18n/utf8_validator_tables.h',
         ],
       }]
     ],
   },
 }