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

base/trace_event/trace_log.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/trace_log.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 #include <utility>
@@ skipping 1342 matching lines @@
         // is in |TraceLog::UpdateTraceEventDuration|.
         AllocationContextTracker::GetInstanceForCurrentThread()
             ->PopPseudoStackFrame(name);
     }
   }
 
   return handle;
 }
 
 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,
     const unsigned long long* arg_values,
     std::unique_ptr<ConvertableToTraceFormat>* convertable_values,
     unsigned int flags) {
   HEAP_PROFILER_SCOPED_IGNORE;
   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));
 }
 
 // May be called when a COMPELETE event ends and the unfinished event has been
 // recycled (phase == TRACE_EVENT_PHASE_END and trace_event == NULL).
 std::string TraceLog::EventToConsoleMessage(unsigned char phase,
                                             const TimeTicks& timestamp,
                                             TraceEvent* trace_event) {
   HEAP_PROFILER_SCOPED_IGNORE;
   AutoLock thread_info_lock(thread_info_lock_);
@@ skipping 392 matching lines @@
 }
 
 ScopedTraceBinaryEfficient::~ScopedTraceBinaryEfficient() {
   if (*category_group_enabled_) {
     TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_group_enabled_, name_,
                                                 event_handle_);
   }
 }
 
 }  // namespace trace_event_internal