mac: Hook up allocator shim.

base/allocator/allocator_shim.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.
 
 #ifndef BASE_ALLOCATOR_ALLOCATOR_SHIM_H_
 #define BASE_ALLOCATOR_ALLOCATOR_SHIM_H_
 
 #include <stddef.h>
 
 #include "base/base_export.h"
@@ skipping 44 matching lines @@
   using ReallocFn = void*(const AllocatorDispatch* self,
                           void* address,
                           size_t size);
   using FreeFn = void(const AllocatorDispatch* self, void* address);
   // Returns the best available estimate for the actual amount of memory
   // consumed by the allocation |address|. If possible, this should include
   // heap overhead or at least a decent estimate of the full cost of the
   // allocation. If no good estimate is possible, returns zero.
   using GetSizeEstimateFn = size_t(const AllocatorDispatch* self,
                                    void* address);
+  using BatchMallocFn = unsigned(const AllocatorDispatch* self,

[DmitrySkiba, 2017/01/10 21:48:34]

We should also add a callback for free_definite_size, which is now just calls
free, which I suspect slightly regresses performance (because free has to find
allocation size again).

Also, how about somehow marking that these are macOS specific? Maybe #ifdef them
out on other platforms?

+                                 size_t size,
+                                 void** results,
+                                 unsigned num_requested);
+  using BatchFreeFn = void(const AllocatorDispatch* self,
+                           void** to_be_freed,
+                           unsigned num_to_be_freed);
 
   AllocFn* const alloc_function;
   AllocZeroInitializedFn* const alloc_zero_initialized_function;
   AllocAlignedFn* const alloc_aligned_function;
   ReallocFn* const realloc_function;
   FreeFn* const free_function;
   GetSizeEstimateFn* const get_size_estimate_function;
+  BatchMallocFn* const batch_malloc_function;
+  BatchFreeFn* const batch_free_function;
 
   const AllocatorDispatch* next;
 
   // |default_dispatch| is statically defined by one (and only one) of the
   // allocator_shim_default_dispatch_to_*.cc files, depending on the build
   // configuration.
   static const AllocatorDispatch default_dispatch;
 };
 
 // When true makes malloc behave like new, w.r.t calling the new_handler if
@@ skipping 12 matching lines @@
 
 // Test-only. Rationale: (1) lack of use cases; (2) dealing safely with a
 // removal of arbitrary elements from a singly linked list would require a lock
 // in malloc(), which we really don't want.
 BASE_EXPORT void RemoveAllocatorDispatchForTesting(AllocatorDispatch* dispatch);
 
 }  // namespace allocator
 }  // namespace base
 
 #endif  // BASE_ALLOCATOR_ALLOCATOR_SHIM_H_