Implement about:tracing UI for the sampling profiler (Chromium part)

components/tracing/child_trace_message_filter.h

Index: components/tracing/child_trace_message_filter.h
diff --git a/components/tracing/child_trace_message_filter.h b/components/tracing/child_trace_message_filter.h
index 9631ced7b3487a40f18c306dc8272d18f46b508e..df514d4fc739cc1f4c89dc478d846a9f77dcbe1a 100644
--- a/components/tracing/child_trace_message_filter.h
+++ b/components/tracing/child_trace_message_filter.h
@@ -34,6 +34,9 @@ class ChildTraceMessageFilter : public IPC::ChannelProxy::MessageFilter {
                       base::TimeTicks browser_time,
                       int mode);
   void OnEndTracing();
+  void OnBeginContinuousSamplingTracing(base::TimeTicks browser_time);
+  void OnEndContinuousSamplingTracing();
+  void OnShowContinuousSamplingTracing();
   void OnGetTraceBufferPercentFull();
   void OnSetWatchEvent(const std::string& category_name,
                        const std::string& event_name);
@@ -42,6 +45,8 @@ class ChildTraceMessageFilter : public IPC::ChannelProxy::MessageFilter {
   // Callback from trace subsystem.
   void OnTraceDataCollected(
       const scoped_refptr<base::RefCountedString>& events_str_ptr);
+  void OnContinuousSamplingTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& events_str_ptr);
   void OnTraceNotification(int notification);
 
   IPC::Channel* channel_;