Add a GUID to base::SharedMemoryHandle.

base/memory/shared_memory_handle_win.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 "base/logging.h"
+#include "base/unguessable_token.h"
 
 namespace base {
 
 SharedMemoryHandle::SharedMemoryHandle()
     : handle_(nullptr), ownership_passes_to_ipc_(false) {}
 
-SharedMemoryHandle::SharedMemoryHandle(HANDLE h)
-    : handle_(h), ownership_passes_to_ipc_(false) {}
-
-SharedMemoryHandle::SharedMemoryHandle(const SharedMemoryHandle& handle)
-    : handle_(handle.handle_),
-      ownership_passes_to_ipc_(handle.ownership_passes_to_ipc_) {}
-
-SharedMemoryHandle& SharedMemoryHandle::operator=(
-    const SharedMemoryHandle& handle) {
-  if (this == &handle)
-    return *this;
-
-  handle_ = handle.handle_;
-  ownership_passes_to_ipc_ = handle.ownership_passes_to_ipc_;
-  return *this;
-}
+SharedMemoryHandle(HANDLE h, const base::UnguessableToken& guid)
+    : handle_(h), ownership_passes_to_ipc_(false), guid_(guid) {}
 
 void SharedMemoryHandle::Close() const {
   DCHECK(handle_ != nullptr);
   ::CloseHandle(handle_);
 }
 
 bool SharedMemoryHandle::IsValid() const {
   return handle_ != nullptr;
 }
 
 SharedMemoryHandle SharedMemoryHandle::Duplicate() const {
   HANDLE duped_handle;
   ProcessHandle process = GetCurrentProcess();
   BOOL success = ::DuplicateHandle(process, handle_, process, &duped_handle, 0,
                                    FALSE, DUPLICATE_SAME_ACCESS);
   if (!success)
     return SharedMemoryHandle();
 
-  base::SharedMemoryHandle handle(duped_handle);
+  base::SharedMemoryHandle handle(duped_handle, GetGUID());

[Nico, 2017/05/04 17:42:13]

So several handles can have the same guid? Document that in header somehow.

[erikchen, 2017/05/04 19:21:13]

Done.

   handle.SetOwnershipPassesToIPC(true);
   return handle;
 }
 
 HANDLE SharedMemoryHandle::GetHandle() const {
   return handle_;
 }
 
 void SharedMemoryHandle::SetOwnershipPassesToIPC(bool ownership_passes) {
   ownership_passes_to_ipc_ = ownership_passes;
 }
 
 bool SharedMemoryHandle::OwnershipPassesToIPC() const {
   return ownership_passes_to_ipc_;
 }
 
 }  // namespace base