base/ header cleanup. Forward declaration instead of including.

chrome/browser/platform_util_common_linux.cc

 // Copyright (c) 2010 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 "chrome/browser/platform_util.h"
 
 #include <gtk/gtk.h>
 
 #include "app/gtk_util.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/process_util.h"
+#include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/process_watcher.h"
 #include "chrome/browser/gtk/gtk_util.h"
 #include "gfx/native_widget_types.h"
 #include "googleurl/src/gurl.h"
 
 namespace {
 
 void SetDialogTitle(GtkWidget* dialog, const string16& title) {
   gtk_window_set_title(GTK_WINDOW(dialog), UTF16ToUTF8(title).c_str());
@@ skipping 101 matching lines @@
     // do nothing.
   } else {
     modifier = "unknown";
   }
 #endif
 
   return ASCIIToUTF16(modifier);
 }
 
 }  // namespace platform_util