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

base/trace_event/trace_log.cc

Index: base/trace_event/trace_log.cc
diff --git a/base/trace_event/trace_log.cc b/base/trace_event/trace_log.cc
index cc40ba98eb31f5c0b5e370bacbf8ca5b232a15dd..d9839361d81936a6d6ab773b7055558e7dadffe9 100644
--- a/base/trace_event/trace_log.cc
+++ b/base/trace_event/trace_log.cc
@@ -1360,8 +1360,10 @@ TraceEventHandle TraceLog::AddTraceEventWithThreadIdAndTimestamp(
 }
 
 void TraceLog::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,
@@ -1372,15 +1374,16 @@ void TraceLog::AddMetadataEvent(
   std::unique_ptr<TraceEvent> trace_event(new TraceEvent);
   int thread_id = static_cast<int>(base::PlatformThread::CurrentId());
   ThreadTicks thread_now = ThreadNow();
-  TimeTicks now = OffsetNow();
+  TimeTicks offset_event_timestamp = OffsetTimestamp(timestamp);
+
   AutoLock lock(lock_);
-  trace_event->Initialize(
-      thread_id, now, thread_now, TRACE_EVENT_PHASE_METADATA,
-      category_group_enabled, name,
-      trace_event_internal::kGlobalScope,  // scope
-      trace_event_internal::kNoId,         // id
-      trace_event_internal::kNoId,         // bind_id
-      num_args, arg_names, arg_types, arg_values, convertable_values, flags);
+  trace_event->Initialize(thread_id, offset_event_timestamp, thread_now, phase,
+                          category_group_enabled, name,
+                          trace_event_internal::kGlobalScope,  // scope
+                          trace_event_internal::kNoId,         // id
+                          trace_event_internal::kNoId,         // bind_id
+                          num_args, arg_names, arg_types, arg_values,
+                          convertable_values, flags);
   metadata_events_.push_back(std::move(trace_event));
 }