[Tracing Clock Sync] Implement clock sync in Chrome

content/browser/tracing/power_tracing_agent.h

 // Copyright 2015 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_POWER_TRACING_AGENT_H_
 #define CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/threading/thread.h"
 #include "base/trace_event/tracing_agent.h"
@@ skipping 30 matching lines @@
   // by the Singleton class.
   friend struct base::DefaultSingletonTraits<PowerTracingAgent>;
 
   // Constructor.
   PowerTracingAgent();
   ~PowerTracingAgent() override;
 
   void OnStopTracingDone(const StopAgentTracingCallback& callback,
                          const scoped_refptr<base::RefCountedString>& result);
 
+  void TraceOnThread();
   void FlushOnThread(const StopAgentTracingCallback& callback);
+  void RecordClockSyncMarkerOnThread(
+      int sync_id,
+      const RecordClockSyncMarkerCallback& callback);
 
+  base::Thread thread_;
   scoped_ptr<BattorPowerTraceProvider> battor_trace_provider_;
-  bool is_tracing_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerTracingAgent);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_