win: More attachment brokering for PlatformFileForTransit.

ipc/ipc_platform_file.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 "build/build_config.h"
 #include "ipc/ipc_platform_file.h"
 
 #if defined(OS_POSIX)
 #include <unistd.h>
 #endif
 
 namespace IPC {
 
 PlatformFileForTransit GetFileHandleForProcess(base::PlatformFile handle,
                                                base::ProcessHandle process,
                                                bool close_source_handle) {
-  IPC::PlatformFileForTransit out_handle;
 #if defined(OS_WIN)
   HANDLE raw_handle = INVALID_HANDLE_VALUE;
   DWORD options = DUPLICATE_SAME_ACCESS;
   if (close_source_handle)
     options |= DUPLICATE_CLOSE_SOURCE;
   if (handle == INVALID_HANDLE_VALUE ||
-      !::DuplicateHandle(::GetCurrentProcess(), handle, process, &raw_handle, 0,
-                         FALSE, options)) {
-    out_handle = IPC::InvalidPlatformFileForTransit();
-  } else {
-    out_handle =
-        IPC::PlatformFileForTransit(raw_handle, base::GetProcId(process));
-    out_handle.SetOwnershipPassesToIPC(true);
+      !::DuplicateHandle(::GetCurrentProcess(), handle, ::GetCurrentProcess(),
+                         &raw_handle, 0, FALSE, options)) {
+    return IPC::InvalidPlatformFileForTransit();
   }
+
+  IPC::PlatformFileForTransit out_handle = IPC::PlatformFileForTransit(
+      raw_handle, base::GetCurrentProcId());
+  out_handle.SetOwnershipPassesToIPC(true);
+  return out_handle;
 #elif defined(OS_POSIX)
   // If asked to close the source, we can simply re-use the source fd instead of
   // dup()ing and close()ing.
   // When we're not closing the source, we need to duplicate the handle and take
   // ownership of that. The reason is that this function is often used to
   // generate IPC messages, and the handle must remain valid until it's sent to
   // the other process from the I/O thread. Without the dup, calling code might
   // close the source handle before the message is sent, creating a race
   // condition.
   int fd = close_source_handle ? handle : ::dup(handle);
-  out_handle = base::FileDescriptor(fd, true);
+  return base::FileDescriptor(fd, true);
 #else
   #error Not implemented.
 #endif
-  return out_handle;
 }
 
 PlatformFileForTransit TakeFileHandleForProcess(base::File file,
                                                 base::ProcessHandle process) {
   return GetFileHandleForProcess(file.TakePlatformFile(), process, true);
 }
 
 }  // namespace IPC