Update tracing framework to optionally use a ringbuffer.

content/browser/tracing/trace_controller_impl.h

 // Copyright (c) 2012 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_TRACE_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TRACING_TRACE_CONTROLLER_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 25 matching lines @@
   //   all categories are traced.
   // Else if included_categories is non-empty, only those are traced.
   // Else if excluded_categories is non-empty, everything but those are traced.
   bool BeginTracing(TraceSubscriber* subscriber,
                     const std::vector<std::string>& included_categories,
                     const std::vector<std::string>& excluded_categories);
 
   // TraceController implementation:
   virtual bool BeginTracing(TraceSubscriber* subscriber,
                             const std::string& categories) OVERRIDE;
+  virtual bool BeginTracing(TraceSubscriber* subscriber,
+                            const std::string& categories,
+                            bool continuous_tracing) OVERRIDE;
   virtual  bool EndTracingAsync(TraceSubscriber* subscriber) OVERRIDE;
   virtual bool GetTraceBufferPercentFullAsync(
       TraceSubscriber* subscriber) OVERRIDE;
   virtual bool SetWatchEvent(TraceSubscriber* subscriber,
                              const std::string& category_name,
                              const std::string& event_name) OVERRIDE;
   virtual bool CancelWatchEvent(TraceSubscriber* subscriber) OVERRIDE;
   virtual void CancelSubscriber(TraceSubscriber* subscriber) OVERRIDE;
 
  private:
@@ skipping 43 matching lines @@
   // Pending acks for GetTraceBufferPercentFullAsync:
   int pending_bpf_ack_count_;
   float maximum_bpf_;
   bool is_tracing_;
   bool is_get_categories_;
   std::set<std::string> known_categories_;
   std::vector<std::string> included_categories_;
   std::vector<std::string> excluded_categories_;
   std::string watch_category_;
   std::string watch_name_;
+  bool continuous_tracing_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceControllerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_TRACE_CONTROLLER_IMPL_H_