Remove unused fields from //content.

content/browser/tracing/tracing_controller_impl.h

 // Copyright (c) 2013 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.
 
 #ifndef CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 173 matching lines @@
   size_t approximate_event_count_;
 
   // Pending acks for memory RequestGlobalDumpPoint.
   int pending_memory_dump_ack_count_;
   int failed_memory_dump_count_;
   TraceMessageFilterSet pending_memory_dump_filters_;
   uint64_t pending_memory_dump_guid_;
   base::trace_event::MemoryDumpCallback pending_memory_dump_callback_;
 
   std::vector<base::trace_event::TracingAgent*> additional_tracing_agents_;
-  int clock_sync_id_;
   int pending_clock_sync_ack_count_;
   base::OneShotTimer clock_sync_timer_;
 
   bool is_tracing_;
   bool is_monitoring_;
 
   GetCategoriesDoneCallback pending_get_categories_done_callback_;
   GetTraceBufferUsageCallback pending_trace_buffer_usage_callback_;
 
   std::string watch_category_name_;
   std::string watch_event_name_;
   WatchEventCallback watch_event_callback_;
 
   base::ObserverList<TraceMessageFilterObserver>
       trace_message_filter_observers_;
 
   std::set<std::string> known_category_groups_;
   std::set<TracingUI*> tracing_uis_;
   scoped_refptr<TraceDataSink> trace_data_sink_;
   scoped_refptr<TraceDataSink> monitoring_data_sink_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingControllerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_