Update tracing framework to optionally use a ringbuffer.

components/tracing/child_trace_message_filter.cc

Index: components/tracing/child_trace_message_filter.cc
diff --git a/components/tracing/child_trace_message_filter.cc b/components/tracing/child_trace_message_filter.cc
index 161c778c450ff827243d70cbecc4002ca4c6fd55..b8af00f0a6f2f8d12f52d94eb600c34c4d699d8f 100644
--- a/components/tracing/child_trace_message_filter.cc
+++ b/components/tracing/child_trace_message_filter.cc
@@ -48,7 +48,8 @@ ChildTraceMessageFilter::~ChildTraceMessageFilter() {}
 void ChildTraceMessageFilter::OnBeginTracing(
     const std::vector<std::string>& included_categories,
     const std::vector<std::string>& excluded_categories,
-    base::TimeTicks browser_time) {
+    base::TimeTicks browser_time,
+    bool continuous_tracing) {
 #if defined(__native_client__)
   // NaCl and system times are offset by a bit, so subtract some time from
   // the captured timestamps. The value might be off by a bit due to messaging
@@ -59,6 +60,7 @@ void ChildTraceMessageFilter::OnBeginTracing(
 #endif
   TraceLog::GetInstance()->SetEnabled(included_categories,
                                       excluded_categories);
+  TraceLog::GetInstance()->SetContinuousTracing(continuous_tracing);
 }
 
 void ChildTraceMessageFilter::OnEndTracing() {