Add methods to base::SharedMemory to replace common SharedMemoryHandle operations.

base/memory/shared_memory_posix.cc

 // Copyright (c) 2012 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 <errno.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
@@ skipping 158 matching lines @@
   DCHECK_GE(handle.fd, 0);
   if (close(handle.fd) < 0)
     DPLOG(ERROR) << "close";
 }
 
 // static
 size_t SharedMemory::GetHandleLimit() {
   return base::GetMaxFds();
 }
 
+// static
+SharedMemoryHandle SharedMemory::ShallowCopyHandle(
+    const SharedMemoryHandle& handle) {
+  SharedMemoryHandle new_handle = handle;
+  new_handle.auto_close = false;
+  return new_handle;
+}
+
+// static
+SharedMemoryHandle SharedMemory::DeepCopyHandle(
+    const SharedMemoryHandle& handle,
+    bool clean_up_resources_on_destruction) {
+  int duped_handle = HANDLE_EINTR(dup(handle.fd));
+  if (duped_handle < 0)
+    return base::SharedMemory::NULLHandle();
+  return base::FileDescriptor(duped_handle, clean_up_resources_on_destruction);
+}
+
 bool SharedMemory::CreateAndMapAnonymous(size_t size) {
   return CreateAnonymous(size) && Map(size);
 }
 
 #if !defined(OS_ANDROID)
 // Chromium mostly only uses the unique/private shmem as specified by
 // "name == L"". The exception is in the StatsTable.
 // TODO(jrg): there is no way to "clean up" all unused named shmem if
 // we restart from a crash.  (That isn't a new problem, but it is a problem.)
 // In case we want to delete it later, it may be useful to save the value
@@ skipping 335 matching lines @@
 
   if (close_self) {
     Unmap();
     Close();
   }
 
   return true;
 }
 
 }  // namespace base