Add a StatisticsDeltaReader class and use cases

base/base.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 587 matching lines @@
         'synchronization/condition_variable_unittest.cc',
         'synchronization/lock_unittest.cc',
         'synchronization/waitable_event_unittest.cc',
         'synchronization/waitable_event_watcher_unittest.cc',
         'sys_info_unittest.cc',
         'system_monitor/system_monitor_unittest.cc',
         'task_runner_util_unittest.cc',
         'template_util_unittest.cc',
         'test/expectations/expectation_unittest.cc',
         'test/expectations/parser_unittest.cc',
+        'test/statistics_delta_reader_unittest.cc',
         'test/test_reg_util_win_unittest.cc',
         'test/trace_event_analyzer_unittest.cc',
         'threading/non_thread_safe_unittest.cc',
         'threading/platform_thread_unittest.cc',
         'threading/sequenced_worker_pool_unittest.cc',
         'threading/simple_thread_unittest.cc',
         'threading/thread_checker_unittest.cc',
         'threading/thread_collision_warner_unittest.cc',
         'threading/thread_id_name_manager_unittest.cc',
         'threading/thread_local_storage_unittest.cc',
@@ skipping 286 matching lines @@
         'test/scoped_path_override.cc',
         'test/scoped_path_override.h',
         'test/sequenced_task_runner_test_template.cc',
         'test/sequenced_task_runner_test_template.h',
         'test/sequenced_worker_pool_owner.cc',
         'test/sequenced_worker_pool_owner.h',
         'test/simple_test_clock.cc',
         'test/simple_test_clock.h',
         'test/simple_test_tick_clock.cc',
         'test/simple_test_tick_clock.h',
+        'test/statistics_delta_reader.cc',
+        'test/statistics_delta_reader.h',
         'test/task_runner_test_template.cc',
         'test/task_runner_test_template.h',
         'test/test_file_util.cc',
         'test/test_file_util.h',
         'test/test_file_util_android.cc',
         'test/test_file_util_linux.cc',
         'test/test_file_util_mac.cc',
         'test/test_file_util_posix.cc',
         'test/test_file_util_win.cc',
         'test/test_listener_ios.h',
@@ skipping 430 matching lines @@
             'base_unittests.isolate',
           ],
           'sources': [
             'base_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }