Revert of Revert of Make SharedMemoryHandle a class on Mac.

base/memory/shared_memory_win.cc

 // Copyright (c) 2011 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.h"
 
 #include <aclapi.h>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 26 matching lines @@
 
 SharedMemory::SharedMemory(const std::wstring& name)
     : mapped_file_(NULL),
       memory_(NULL),
       read_only_(false),
       requested_size_(0),
       mapped_size_(0),
       name_(name) {
 }
 
-SharedMemory::SharedMemory(SharedMemoryHandle handle, bool read_only)
+SharedMemory::SharedMemory(const SharedMemoryHandle& handle, bool read_only)
     : mapped_file_(handle),
       memory_(NULL),
       read_only_(read_only),
       requested_size_(0),
       mapped_size_(0) {
 }
 
-SharedMemory::SharedMemory(SharedMemoryHandle handle,
+SharedMemory::SharedMemory(const SharedMemoryHandle& handle,
                            bool read_only,
                            ProcessHandle process)
     : mapped_file_(NULL),
       memory_(NULL),
       read_only_(read_only),
       requested_size_(0),
       mapped_size_(0) {
   ::DuplicateHandle(process, handle,
                     GetCurrentProcess(), &mapped_file_,
                     read_only_ ? FILE_MAP_READ : FILE_MAP_READ |
@@ skipping 197 matching lines @@
     CloseHandle(mapped_file_);
     mapped_file_ = NULL;
   }
 }
 
 SharedMemoryHandle SharedMemory::handle() const {
   return mapped_file_;
 }
 
 }  // namespace base