tracing: Simplify TraceEventMemoryOverhead, use an enum insted of a map

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 380 matching lines @@
     thread_local_event_buffer = new ThreadLocalEventBuffer(this);
     thread_local_event_buffer_.Set(thread_local_event_buffer);
   }
 }
 
 bool TraceLog::OnMemoryDump(const MemoryDumpArgs& args,
                             ProcessMemoryDump* pmd) {
   // TODO(ssid): Use MemoryDumpArgs to create light dumps when requested
   // (crbug.com/499731).
   TraceEventMemoryOverhead overhead;
-  overhead.Add("TraceLog", sizeof(*this));
+  overhead.Add(TraceEventMemoryOverhead::kOther, sizeof(*this));
   {
     AutoLock lock(lock_);
     if (logged_events_)
       logged_events_->EstimateTraceMemoryOverhead(&overhead);
 
     for (auto& metadata_event : metadata_events_)
       metadata_event->EstimateTraceMemoryOverhead(&overhead);
   }
   overhead.AddSelf();
   overhead.DumpInto("tracing/main_trace_log", pmd);
@@ skipping 1259 matching lines @@
       category.set_state_flag(TraceCategory::ENABLED_FOR_ETW_EXPORT);
     } else {
       category.clear_state_flag(TraceCategory::ENABLED_FOR_ETW_EXPORT);
     }
   }
 }
 #endif  // defined(OS_WIN)
 
 void ConvertableToTraceFormat::EstimateTraceMemoryOverhead(
     TraceEventMemoryOverhead* overhead) {
-  overhead->Add("ConvertableToTraceFormat(Unknown)", sizeof(*this));
+  overhead->Add(TraceEventMemoryOverhead::kConvertableToTraceFormat,
+                sizeof(*this));
 }
 
 void TraceLog::AddAsyncEnabledStateObserver(
     WeakPtr<AsyncEnabledStateObserver> listener) {
   AutoLock lock(lock_);
   async_observers_.insert(
       std::make_pair(listener.get(), RegisteredAsyncObserver(listener)));
 }
 
 void TraceLog::RemoveAsyncEnabledStateObserver(
@@ skipping 42 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