Convert string16 to base::string16 in content.

content/shell/browser/shell_gtk.cc

 // 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.
 
 #include "content/shell/browser/shell.h"
 
 #include <gdk/gdkkeysyms.h>
 #include <gtk/gtk.h>
 
 #include "base/logging.h"
@@ skipping 317 matching lines @@
 }
 
 gboolean Shell::OnReloadKeyPressed(GtkAccelGroup* accel_group,
                                    GObject* acceleratable,
                                    guint keyval,
                                    GdkModifierType modifier) {
   Reload();
   return TRUE;
 }
 
-void Shell::PlatformSetTitle(const string16& title) {
+void Shell::PlatformSetTitle(const base::string16& title) {
   if (headless_)
     return;
 
   std::string title_utf8 = UTF16ToUTF8(title);
   gtk_window_set_title(GTK_WINDOW(window_), title_utf8.c_str());
 }
 
 }  // namespace content