allocator/Windows: delete the old non-unified allocator-shim

base/allocator/allocator_shim_win.h

Index: base/allocator/allocator_shim_win.h
diff --git a/base/allocator/allocator_shim_win.h b/base/allocator/allocator_shim_win.h
deleted file mode 100644
index d19a9896372be8617c12f3b8016aac92c99a0fe1..0000000000000000000000000000000000000000
--- a/base/allocator/allocator_shim_win.h
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2016 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_ALLOCATOR_ALLOCATOR_SHIM_WIN_H_
-#define BASE_ALLOCATOR_ALLOCATOR_SHIM_WIN_H_
-
-#include <stddef.h>
-
-namespace base {
-namespace allocator {
-// Used to indicate that the shim is actually in place.
-extern bool g_is_win_shim_layer_initialized;
-}  // namespace allocator
-}  // namespace base
-
-#endif  // BASE_ALLOCATOR_ALLOCATOR_SHIM_WIN_H_