chrome: Update include paths of string_split.h to its new location.

chrome/renderer/spellchecker/spellcheck_worditerator_unittest.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 <string>
 #include <vector>
 
 #include "base/format_macros.h"
 #include "base/stringprintf.h"
-#include "base/string_split.h"
+#include "base/strings/string_split.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/renderer/spellchecker/spellcheck_worditerator.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 struct TestCase {
     const char* language;
     bool allow_contraction;
     const wchar_t* expected_words;
@@ skipping 219 matching lines @@
   }
 
   // Test initialization fails when no default language is set.
   {
     SpellcheckCharAttribute attributes;
 
     SpellcheckWordIterator iterator;
     EXPECT_FALSE(iterator.Initialize(&attributes, true));
   }
 }