Clean up sparse_histogram.h header

ios/chrome/browser/net/metrics_network_client.mm

 // Copyright 2013 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.
 
 #import "ios/chrome/browser/net/metrics_network_client.h"
 
 #import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
-#include "base/metrics/sparse_histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ios/chrome/browser/net/metrics_network_client_manager.h"
 #include "ios/web/public/url_util.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_request.h"
 
 @interface MetricsNetworkClient () {
   BOOL _histogramUpdated;
   // Pointer to the load time record for this request. This will be created
@@ skipping 56 matching lines @@
     [self updateHistogram:netErrorCode];
   }
 }
 
 - (void)didFinishLoading {
   [super didFinishLoading];
   [self updateHistogram:net::OK];
 }
 
 @end