Use a direct include of strings headers in content/browser/, part 1.

content/browser/browser_plugin/browser_plugin_guest.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/browser/browser_plugin/browser_plugin_guest.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/message_loop.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/browser_plugin/browser_plugin_embedder.h"
 #include "content/browser/browser_plugin/browser_plugin_guest_helper.h"
 #include "content/browser/browser_plugin/browser_plugin_guest_manager.h"
 #include "content/browser/browser_plugin/browser_plugin_host_factory.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
@@ skipping 1538 matching lines @@
                    base::Value::CreateStringValue(request_method));
   request_info.Set(browser_plugin::kURL, base::Value::CreateStringValue(url));
 
   SendMessageToEmbedder(
       new BrowserPluginMsg_RequestPermission(instance_id(),
           BrowserPluginPermissionTypeDownload, permission_request_id,
           request_info));
 }
 
 }  // namespace content