Start refactoring Windows allocator shim in prep for hooking in generic allocator shim on Windows.

base/allocator/winheap_stubs_win.h

+// 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.
+
+// Thin allocation wrappers for the windows heap. This file should be deleted
+// once the win-specific allocation shim has been removed, and the generic shim
+// has becaome the default.
+
+#ifndef BASE_ALLOCATOR_WINHEAP_STUBS_H_
+#define BASE_ALLOCATOR_WINHEAP_STUBS_H_
+
+#include <stdint.h>
+
+namespace base {
+namespace allocator {
+
+// Set to true if the link-time magic has successfully hooked into the CRT's
+// heap initialization.
+extern bool g_is_win_shim_layer_initialized;
+
+// Thin wrappers to implement the standard C allocation semantics on the
+// CRT's Windows heap.
+void* WinHeapMalloc(size_t size);
+void WinHeapFree(void* size);
+void* WinHeapRealloc(void* ptr, size_t size);
+
+// Call the new handler, if one has been set.
+// Returns true on successfully calling the handler, false otherwise.
+bool WinCallNewHandler(size_t size);
+
+}  // namespace allocator
+}  // namespace base
+
+#endif  // BASE_ALLOCATOR_WINHEAP_STUBS_H_