Use utf_string_conversions header in more places.

app/gtk_dnd_util.cc

 // Copyright (c) 2009 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 "app/gtk_dnd_util.h"
 
-#include "base/string_util.h"
 #include "base/logging.h"
 #include "base/pickle.h"
+#include "base/utf_string_conversions.h"
 #include "googleurl/src/gurl.h"
 
 static const int kBitsPerByte = 8;
 
 // static
 GdkAtom GtkDndUtil::GetAtomForTarget(int target) {
   switch (target) {
     case CHROME_TAB:
       static GdkAtom tab_atom = gdk_atom_intern(
           const_cast<char*>("application/x-chrome-tab"), false);
@@ skipping 162 matching lines @@
 
   for (size_t i = 0; uris[i] != NULL; ++i) {
     GURL url(uris[i]);
     if (url.is_valid())
       urls->push_back(url);
   }
 
   g_strfreev(uris);
   return true;
 }