arc: enable Android tracing in verified-boot mode

chrome/browser/chromeos/trace/sys_trace_agent.h

+// Copyright 2016 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 CHROME_BROWSER_CHROMEOS_TRACE_SYS_TRACE_AGENT_H_
+#define CHROME_BROWSER_CHROMEOS_TRACE_SYS_TRACE_AGENT_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/task_runner.h"
+#include "base/trace_event/tracing_agent.h"
+
+namespace base {
+template <typename Type>
+struct DefaultSingletonTraits;
+}
+
+namespace chromeos {
+
+// A wrapper for controlling system tracing on Chrome OS.
+class SysTraceAgent : public base::trace_event::TracingAgent {
+ public:
+  // Gets the Singleton of this class.
+  static SysTraceAgent* GetInstance();
+
+  // Overrides TracingAgent functions.
+  std::string GetTracingAgentName() override;
+
+  std::string GetTraceEventLabel() override;
+
+  void StopAgentTracing(const StopAgentTracingCallback& callback) override;
+
+  void StartAgentTracing(const base::trace_event::TraceConfig& trace_config,
+                         const StartAgentTracingCallback& callback) override;
+
+  void SetStopAgentTracingTaskRunner(
+      scoped_refptr<base::TaskRunner> task_runner);
+
+ private:
+  // This allows constructor and destructor to be private and usable only
+  // by the Singleton class.
+  friend struct base::DefaultSingletonTraits<SysTraceAgent>;
+
+  SysTraceAgent();
+  ~SysTraceAgent() override;
+
+  DISALLOW_COPY_AND_ASSIGN(SysTraceAgent);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_TRACE_SYS_TRACE_AGENT_H_