Use SharedMemoryHandle instead ScopedHandle as ivar for SharedMemory

base/memory/shared_memory_handle.h

 // 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.
 
 #ifndef BASE_MEMORY_SHARED_MEMORY_HANDLE_H_
 #define BASE_MEMORY_SHARED_MEMORY_HANDLE_H_
 
 #include <stddef.h>
 
 #include "build/build_config.h"
@@ skipping 82 matching lines @@
   // Returns false on a failure to determine the size. On success, populates the
   // output variable |size|.
   bool GetSize(size_t* size) const;
 
   // The SharedMemoryHandle must be valid.
   // Returns whether the SharedMemoryHandle was successfully mapped into memory.
   // On success, |memory| is an output variable that contains the start of the
   // mapped memory.
   bool MapAt(off_t offset, size_t bytes, void** memory, bool read_only);
 #elif defined(OS_WIN)
+  // Takes implicit ownership of |h|.
   SharedMemoryHandle(HANDLE h);
 
   HANDLE GetHandle() const;
 #else
   // This constructor is deprecated, as it fails to propagate the GUID, which
   // will be added in the near future.
   // TODO(rockot): Remove this constructor once Mojo supports GUIDs.
   // https://crbug.com/713763.
   explicit SharedMemoryHandle(const base::FileDescriptor& file_descriptor);
 
@@ skipping 50 matching lines @@
   // Defaults to |false|.
   bool ownership_passes_to_ipc_;
 #else
   FileDescriptor file_descriptor_;
 #endif
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_SHARED_MEMORY_HANDLE_H_