Delete unused files.

webkit/base/file_path_string_conversions.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 "webkit/base/file_path_string_conversions.h"
-
-#include "third_party/WebKit/public/platform/WebString.h"
-
-namespace webkit_base {
-
-base::FilePath::StringType WebStringToFilePathString(
-    const WebKit::WebString& str) {
-  return base::FilePath::FromUTF16Unsafe(str).value();
-}
-
-WebKit::WebString FilePathStringToWebString(
-    const base::FilePath::StringType& str) {
-  return base::FilePath(str).AsUTF16Unsafe();
-}
-
-base::FilePath WebStringToFilePath(const WebKit::WebString& str) {
-  return base::FilePath::FromUTF16Unsafe(str);
-}
-
-WebKit::WebString FilePathToWebString(const base::FilePath& file_path) {
-  return file_path.AsUTF16Unsafe();
-}
-
-}  // namespace webkit_base