Migrate content/ files to histogram_macros.h includes.

content/child/site_isolation_stats_gatherer.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 "content/child/site_isolation_stats_gatherer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "content/public/common/resource_response_info.h"
 #include "net/http/http_response_headers.h"
 
 namespace content {
 
 namespace {
 
 // The gathering of UMA stats for site isolation is deactivated by default, and
@@ skipping 230 matching lines @@
 }
 
 bool SiteIsolationStatsGatherer::SniffForJS(base::StringPiece data) {
   // The purpose of this function is to try to see if there's any possibility
   // that this data can be JavaScript (superset of JS). Search for "var " for JS
   // detection. This is a real hack and should only be used for stats gathering.
   return data.find("var ") != base::StringPiece::npos;
 }
 
 }  // namespace content