Align base::hash_map with C++11.

base/files/file_path.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.
 
 // FilePath is a container for pathnames stored in a platform's native string
 // type, providing containers for manipulation in according with the
 // platform's conventions for pathnames.  It supports the following path
 // types:
 //
 //                   POSIX            Windows
@@ skipping 435 matching lines @@
 #define PRFilePathLiteral "%s"
 #elif defined(OS_WIN)
 #define FILE_PATH_LITERAL(x) L ## x
 #define PRFilePath "ls"
 #define PRFilePathLiteral L"%ls"
 #endif  // OS_WIN
 
 // Provide a hash function so that hash_sets and maps can contain FilePath
 // objects.
 namespace BASE_HASH_NAMESPACE {
-#if defined(COMPILER_GCC)
 
 template<>
 struct hash<base::FilePath> {
   size_t operator()(const base::FilePath& f) const {
     return hash<base::FilePath::StringType>()(f.value());
   }
 };
 
-#elif defined(COMPILER_MSVC)
-
-inline size_t hash_value(const base::FilePath& f) {
-  return hash_value(f.value());
-}
-
-#endif  // COMPILER
-
 }  // namespace BASE_HASH_NAMESPACE
 
 #endif  // BASE_FILES_FILE_PATH_H_