[Startup Tracing] Remove |is_recording_| in devtool tracing_handler

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 <set>
 #include <string>
 #include <vector>
@@ skipping 32 matching lines @@
       bool* out_enabled,
       base::trace_event::TraceConfig* out_trace_config) override;
   bool CaptureMonitoringSnapshot(
       const scoped_refptr<TraceDataSink>& sink) override;
   bool GetTraceBufferUsage(
       const GetTraceBufferUsageCallback& callback) override;
   bool SetWatchEvent(const std::string& category_name,
                      const std::string& event_name,
                      const WatchEventCallback& callback) override;
   bool CancelWatchEvent() override;
+  bool IsRecording() const override;
 
   void RegisterTracingUI(TracingUI* tracing_ui);
   void UnregisterTracingUI(TracingUI* tracing_ui);
 
   // base::trace_event::MemoryDumpManagerDelegate implementation.
   void RequestGlobalMemoryDump(
       const base::trace_event::MemoryDumpRequestArgs& args,
       const base::trace_event::MemoryDumpCallback& callback) override;
   bool IsCoordinatorProcess() const override;
 
@@ skipping 129 matching lines @@
   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_