base: Update the include paths of base/string_piece.h to its new location.

base/test/values_test_util.h

 // 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.
 
 #ifndef BASE_TEST_VALUES_TEST_UTIL_H_
 #define BASE_TEST_VALUES_TEST_UTIL_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 
 namespace base {
 class DictionaryValue;
 class ListValue;
 class StringValue;
 class Value;
 
 // All the functions below expect that the value for the given key in
 // the given dictionary equals the given expected value.
 
@@ skipping 25 matching lines @@
 
 // Parses |json| as JSON, allowing trailing commas, and returns the
 // resulting value.  If the json fails to parse, causes an EXPECT
 // failure and returns the Null Value (but never a NULL pointer).
 scoped_ptr<Value> ParseJson(base::StringPiece json);
 
 }  // namespace test
 }  // namespace base
 
 #endif  // BASE_TEST_VALUES_TEST_UTIL_H_