tracing v2: Add TraceRingBuffer class.

components/components_tests.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.
 
 {
   'variables': {
     # This turns on e.g. the filename-based detection of which
     # platforms to include source files on (e.g. files ending in
     # _mac.h or _mac.cc are only compiled on MacOSX).
     'chromium_code': 1,
@@ skipping 817 matching lines @@
       'sync_sessions/tab_node_pool_unittest.cc',
     ],
     'syncable_prefs_unittest_sources': [
       'syncable_prefs/pref_model_associator_unittest.cc',
       'syncable_prefs/pref_service_syncable_unittest.cc',
     ],
     'tracing_unittest_sources': [
       'tracing/browser/trace_config_file_unittest.cc',
       'tracing/common/graphics_memory_dump_provider_android_unittest.cc',
       'tracing/common/process_metrics_memory_dump_provider_unittest.cc',
+      'tracing/core/trace_ring_buffer_unittest.cc',
     ],
     'translate_unittest_sources': [
       'translate/core/browser/mock_translate_driver.cc',
       'translate/core/browser/language_state_unittest.cc',
       'translate/core/browser/translate_browser_metrics_unittest.cc',
       'translate/core/browser/translate_language_list_unittest.cc',
       'translate/core/browser/translate_manager_unittest.cc',
       'translate/core/browser/translate_prefs_unittest.cc',
       'translate/core/browser/translate_script_unittest.cc',
       'translate/core/browser/translate_ui_delegate_unittest.cc',
@@ skipping 1125 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }