Share field trial allocator on MacOS

base/memory/shared_memory_handle_mac.cc

 // Copyright 2015 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/memory/shared_memory_handle.h"
 
 #include <mach/mach_vm.h>
 #include <stddef.h>
 #include <sys/mman.h>
 #include <unistd.h>
@@ skipping 159 matching lines @@
 
 bool SharedMemoryHandle::MapAt(off_t offset,
                                size_t bytes,
                                void** memory,
                                bool read_only) {
   DCHECK(IsValid());
   switch (type_) {
     case SharedMemoryHandle::POSIX:
       *memory = mmap(nullptr, bytes, PROT_READ | (read_only ? 0 : PROT_WRITE),
                      MAP_SHARED, file_descriptor_.fd, offset);
-

[Alexei Svitkine (slow), 2016/12/09 22:23:41]

Nit: Remove extra diff here.

       return *memory && *memory != reinterpret_cast<void*>(-1);
     case SharedMemoryHandle::MACH:
       DCHECK_EQ(pid_, GetCurrentProcId());
       kern_return_t kr = mach_vm_map(
           mach_task_self(),
           reinterpret_cast<mach_vm_address_t*>(memory),  // Output parameter
           bytes,
           0,  // Alignment mask
           VM_FLAGS_ANYWHERE, memory_object_, offset,
           FALSE,                                           // Copy
@@ skipping 39 matching lines @@
     case MACH:
       memory_object_ = handle.memory_object_;
       size_ = handle.size_;
       pid_ = handle.pid_;
       ownership_passes_to_ipc_ = handle.ownership_passes_to_ipc_;
       break;
   }
 }
 
 }  // namespace base