Tracing: Added necessary plumbing to make sure clocksync metadata events are always included.

base/trace_event/trace_log.h

Index: base/trace_event/trace_log.h
diff --git a/base/trace_event/trace_log.h b/base/trace_event/trace_log.h
index e4407e81bdcf35c7e1d793bd8b397ddaa4a193c7..2840fd564708ac4b1ae923e96a55d982876af8a0 100644
--- a/base/trace_event/trace_log.h
+++ b/base/trace_event/trace_log.h
@@ -273,8 +273,10 @@ class BASE_EXPORT TraceLog : public MemoryDumpProvider {
 
   // Adds a metadata event that will be written when the trace log is flushed.
   void AddMetadataEvent(
+      char phase,
       const unsigned char* category_group_enabled,
       const char* name,
+      const TimeTicks& timestamp,
       int num_args,
       const char** arg_names,
       const unsigned char* arg_types,