Add a method BrokerDuplicateSharedMemoryHandle() to the sandbox.

content/common/sandbox_init_mac.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 "content/public/common/sandbox_init.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "content/common/sandbox_mac.h"
@@ skipping 56 matching lines @@
 }
 
 bool InitializeSandbox() {
   int sandbox_type = 0;
   base::FilePath allowed_dir;
   if (!GetSandboxTypeFromCommandLine(&sandbox_type, &allowed_dir))
     return true;
   return InitializeSandbox(sandbox_type, allowed_dir);
 }
 
+bool BrokerDuplicateSharedMemoryHandle(
+    const base::SharedMemoryHandle& source_handle,
+    base::ProcessId target_process_id,
+    base::SharedMemoryHandle* target_handle) {
+  *target_handle = base::SharedMemory::DuplicateHandle(source_handle);
+  return base::SharedMemory::IsHandleValid(*target_handle);
+}
+
 extern const char kBootstrapPortNameForNPAPIPlugins[] =
     "org.chromium.sandbox.real_bootstrap_server";
 
 }  // namespace content