Update tracing framework to optionally use a ringbuffer.

content/browser/tracing/trace_controller_impl.h

Index: content/browser/tracing/trace_controller_impl.h
diff --git a/content/browser/tracing/trace_controller_impl.h b/content/browser/tracing/trace_controller_impl.h
index 501f56147de483243c260fdcd5bc9d1ae7281d34..673113de5279e4243c9b499286a9e00d0def8682 100644
--- a/content/browser/tracing/trace_controller_impl.h
+++ b/content/browser/tracing/trace_controller_impl.h
@@ -43,6 +43,9 @@ class TraceControllerImpl : public TraceController {
   // 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;
@@ -106,6 +109,7 @@ class TraceControllerImpl : public TraceController {
   std::vector<std::string> excluded_categories_;
   std::string watch_category_;
   std::string watch_name_;
+  bool continuous_tracing_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceControllerImpl);
 };