[ETW] Fix wrong index in UpdateETWCategoryGroupEnabledFlags resulting in overflow.

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 "base/base_switches.h"
@@ skipping 1700 matching lines @@
 void TraceLog::UpdateETWCategoryGroupEnabledFlags() {
   AutoLock lock(lock_);
   size_t category_index = base::subtle::NoBarrier_Load(&g_category_index);
   // Go through each category and set/clear the ETW bit depending on whether the
   // category is enabled.
   for (size_t i = 0; i < category_index; i++) {
     const char* category_group = g_category_groups[i];
     DCHECK(category_group);
     if (base::trace_event::TraceEventETWExport::IsCategoryGroupEnabled(
             category_group)) {
-      g_category_group_enabled[category_index] |= ENABLED_FOR_ETW_EXPORT;
+      g_category_group_enabled[i] |= ENABLED_FOR_ETW_EXPORT;
     } else {
-      g_category_group_enabled[category_index] &= ~ENABLED_FOR_ETW_EXPORT;
+      g_category_group_enabled[i] &= ~ENABLED_FOR_ETW_EXPORT;
     }
   }
 }
 #endif  // defined(OS_WIN)
 
 void ConvertableToTraceFormat::EstimateTraceMemoryOverhead(
     TraceEventMemoryOverhead* overhead) {
   overhead->Add("ConvertableToTraceFormat(Unknown)", sizeof(*this));
 }
 
@@ skipping 31 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