clang/win: Let some chromium_code targets build with -Wextra.

base/trace_event/trace_event_etw_export_win.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_event_etw_export_win.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "base/strings/string_tokenizer.h"
@@ skipping 159 matching lines @@
 
     // Register the ETW provider. If registration fails then the event logging
     // calls will fail (on XP this call will do nothing).
     EventRegisterChrome();
   }
 
   // Make sure to initialize the map with all the group names. Subsequent
   // modifications will be made by the background thread and only affect the
   // values of the keys (no key addition/deletion). Therefore, the map does not
   // require a lock for access.
-  for (int i = 0; i < ARRAYSIZE(kFilteredEventGroupNames); i++)
+  for (size_t i = 0; i < ARRAYSIZE(kFilteredEventGroupNames); i++)
     categories_status_[kFilteredEventGroupNames[i]] = false;
   categories_status_[kOtherEventsGroupName] = false;
   categories_status_[kDisabledOtherEventsGroupName] = false;
   DCHECK_EQ(kNumberOfCategories, categories_status_.size());
 }
 
 TraceEventETWExport::~TraceEventETWExport() {
   EventUnregisterChrome();
 }
 
@@ skipping 178 matching lines @@
 
 bool TraceEventETWExport::UpdateEnabledCategories() {
   if (etw_match_any_keyword_ == CHROME_Context.MatchAnyKeyword)
     return false;
 
   // If the keyword has changed, update each category.
   // Chrome_Context.MatchAnyKeyword is set by UIforETW (or other ETW trace
   // recording tools) using the ETW infrastructure. This value will be set in
   // all Chrome processes that have registered their ETW provider.
   etw_match_any_keyword_ = CHROME_Context.MatchAnyKeyword;
-  for (int i = 0; i < ARRAYSIZE(kFilteredEventGroupNames); i++) {
+  for (size_t i = 0; i < ARRAYSIZE(kFilteredEventGroupNames); i++) {
     if (etw_match_any_keyword_ & (1ULL << i)) {
       categories_status_[kFilteredEventGroupNames[i]] = true;
     } else {
       categories_status_[kFilteredEventGroupNames[i]] = false;
     }
   }
 
   // Also update the two default categories.
   if (etw_match_any_keyword_ & kOtherEventsKeywordBit) {
     categories_status_[kOtherEventsGroupName] = true;
@@ skipping 37 matching lines @@
 // static
 void TraceEventETWExport::UpdateETWKeyword() {
   if (!IsETWExportEnabled())
     return;
   auto* instance = GetInstance();
   DCHECK(instance);
   instance->UpdateEnabledCategories();
 }
 }  // namespace trace_event
 }  // namespace base