Standardize "net" category trace events

net/dns/host_cache.cc

 // Copyright (c) 2012 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 "net/dns/host_cache.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "net/base/net_errors.h"
+#include "net/base/trace_constants.h"
 #include "net/dns/dns_util.h"
 
 namespace net {
 
 namespace {
 
 #define CACHE_HISTOGRAM_TIME(name, time) \
   UMA_HISTOGRAM_LONG_TIMES("DNS.HostCache." name, time)
 
 #define CACHE_HISTOGRAM_COUNT(name, count) \
@@ skipping 131 matching lines @@
 
 HostCache::Entry* HostCache::LookupInternal(const Key& key) {
   auto it = entries_.find(key);
   return (it != entries_.end()) ? &it->second : nullptr;
 }
 
 void HostCache::Set(const Key& key,
                     const Entry& entry,
                     base::TimeTicks now,
                     base::TimeDelta ttl) {
-  TRACE_EVENT0("net", "HostCache::Set");
+  TRACE_EVENT0(kNetTracingCategory, "HostCache::Set");
   DCHECK(CalledOnValidThread());
   if (caching_is_disabled())
     return;
 
   auto it = entries_.find(key);
   if (it != entries_.end()) {
     bool is_stale = it->second.IsStale(now, network_changes_);
     RecordSet(is_stale ? SET_UPDATE_STALE : SET_UPDATE_VALID, now, &it->second,
               entry);
     // TODO(juliatuttle): Remember some old metadata (hit count or frequency or
@@ skipping 181 matching lines @@
     CACHE_HISTOGRAM_TIME("EraseValid.ValidFor", -stale.expired_by);
   }
 }
 
 void HostCache::RecordEraseAll(EraseReason reason, base::TimeTicks now) {
   for (const auto& it : entries_)
     RecordErase(reason, now, it.second);
 }
 
 }  // namespace net