Change sampler code events phase from instant to meta.

content/browser/tracing/tracing_controller_impl.cc

 // Copyright (c) 2013 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 "content/browser/tracing/tracing_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/cpu.h"
 #include "base/files/file_util.h"
 #include "base/guid.h"
 #include "base/json/string_escape.h"
@@ skipping 270 matching lines @@
       FROM_HERE, base::TimeDelta::FromSeconds(kStartTracingTimeoutSeconds),
       base::Bind(&TracingControllerImpl::OnAllTracingAgentsStarted,
                  base::Unretained(this)));
 
   return true;
 }
 
 void TracingControllerImpl::OnAllTracingAgentsStarted() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  TRACE_EVENT_API_ADD_METADATA_EVENT("IsTimeTicksHighResolution", "value",
-                                     base::TimeTicks::IsHighResolution());
   TRACE_EVENT_API_ADD_METADATA_EVENT(
-      "TraceConfig", "value",
+      TraceLog::GetCategoryGroupEnabled("__metadata"),
+      "IsTimeTicksHighResolution", "value",
+      base::TimeTicks::IsHighResolution());
+  TRACE_EVENT_API_ADD_METADATA_EVENT(
+      TraceLog::GetCategoryGroupEnabled("__metadata"), "TraceConfig", "value",
       start_tracing_trace_config_->AsConvertableToTraceFormat());
 
   // Notify all child processes.
   for (TraceMessageFilterSet::iterator it = trace_message_filters_.begin();
       it != trace_message_filters_.end(); ++it) {
     it->get()->SendBeginTracing(*start_tracing_trace_config_);
   }
 
   if (!start_tracing_done_callback_.is_null())
     start_tracing_done_callback_.Run();
@@ skipping 697 matching lines @@
   const bool global_success = failed_memory_dump_count_ == 0;
   if (!pending_memory_dump_callback_.is_null()) {
     pending_memory_dump_callback_.Run(pending_memory_dump_guid_,
                                       global_success);
     pending_memory_dump_callback_.Reset();
   }
   pending_memory_dump_guid_ = 0;
 }
 
 }  // namespace content