Migrate content/ files to histogram_macros.h includes.

content/renderer/dom_storage/webstoragearea_impl.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 "content/renderer/dom_storage/webstoragearea_impl.h"
 
 #include "base/lazy_instance.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "content/common/dom_storage/dom_storage_messages.h"
 #include "content/renderer/dom_storage/dom_storage_cached_area.h"
 #include "content/renderer/dom_storage/dom_storage_dispatcher.h"
 #include "content/renderer/render_thread_impl.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 
 using blink::WebString;
 using blink::WebURL;
@@ skipping 51 matching lines @@
 void WebStorageAreaImpl::removeItem(
     const WebString& key, const WebURL& page_url) {
   cached_area_->RemoveItem(connection_id_, key, page_url);
 }
 
 void WebStorageAreaImpl::clear(const WebURL& page_url) {
   cached_area_->Clear(connection_id_, page_url);
 }
 
 }  // namespace content