mac: Hook up allocator shim.

base/allocator/allocator_shim_default_dispatch_to_winheap.cc

 // 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.
 
 #include "base/allocator/allocator_shim.h"
 
 #include "base/allocator/winheap_stubs_win.h"
 #include "base/logging.h"
 
 namespace {
@@ skipping 43 matching lines @@
 
 }  // namespace
 
 const AllocatorDispatch AllocatorDispatch::default_dispatch = {
     &DefaultWinHeapMallocImpl,
     &DefaultWinHeapCallocImpl,
     &DefaultWinHeapMemalignImpl,
     &DefaultWinHeapReallocImpl,
     &DefaultWinHeapFreeImpl,
     &DefaultWinHeapGetSizeEstimateImpl,
+    nullptr, /* batch_malloc_function */
+    nullptr, /* batch_free_function */
     nullptr, /* next */
 };