components: Introduce AlarmTimer class and use it for GCM heartbeat

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 72 matching lines @@
             'gcm_driver/gcm_client_impl.h',
             'gcm_driver/gcm_delayed_task_controller.cc',
             'gcm_driver/gcm_delayed_task_controller.h',
             'gcm_driver/gcm_driver_desktop.cc',
             'gcm_driver/gcm_driver_desktop.h',
             'gcm_driver/gcm_stats_recorder_impl.cc',
             'gcm_driver/gcm_stats_recorder_impl.h',
             'gcm_driver/proto/gcm_channel_status.proto',
           ],
         }],
+        ['chromeos == 1', {
+          'dependencies': [
+            'timers',
+          ],
+        }],
       ],
     },
     {
       # GN version: //components/gcm_driver:test_support
       'target_name': 'gcm_driver_test_support',
       'type': 'static_library',
       'dependencies': [
         'gcm_driver',
         '../base/base.gyp:base',
         '../google_apis/gcm/gcm.gyp:gcm_test_support',
@@ skipping 56 matching lines @@
           'variables': {
             'jni_gen_package': 'components/gcm_driver',
           },
           'includes': [ '../build/jni_generator.gypi' ],
         },
       ],
      },
     ],
   ],
 }