[tracing] Add trace events to key heap profiler functions.

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 863 matching lines @@
   }
 
   FinishFlush(gen, discard_events);
 }
 
 // Usually it runs on a different thread.
 void TraceLog::ConvertTraceEventsToTraceFormat(
     std::unique_ptr<TraceBuffer> logged_events,
     const OutputCallback& flush_output_callback,
     const ArgumentFilterPredicate& argument_filter_predicate) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("memory-infra"),

[Primiano Tucci (use gerrit), 2017/07/14 14:45:04]

Hmm I am not sure about this one. In all honesty having TRACE_EVENT macros
within TraceLog itself makes me a bit worried.  can you remove this?

+               "TraceLog::ConvertTraceEventsToTraceFormat");
   if (flush_output_callback.is_null())
     return;
 
   HEAP_PROFILER_SCOPED_IGNORE;
   // The callback need to be called at least once even if there is no events
   // to let the caller know the completion of flush.
   scoped_refptr<RefCountedString> json_events_str_ptr = new RefCountedString();
   while (const TraceBufferChunk* chunk = logged_events->NextChunk()) {
     for (size_t j = 0; j < chunk->size(); ++j) {
       size_t size = json_events_str_ptr->size();
@@ skipping 818 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