diff -r 000000000000 -r 6474c204b198 netwerk/ipc/RemoteOpenFileParent.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/ipc/RemoteOpenFileParent.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/net/RemoteOpenFileParent.h"
+#include "mozilla/unused.h"
+#include "nsEscape.h"
+
+#if !defined(XP_WIN) && !defined(MOZ_WIDGET_COCOA)
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
+namespace mozilla {
+namespace net {
+
+bool
+RemoteOpenFileParent::OpenSendCloseDelete()
+{
+#if defined(XP_WIN) || defined(MOZ_WIDGET_COCOA)
+  MOZ_CRASH("OS X and Windows shouldn't be doing IPDL here");
+#else
+
+  // TODO: make this async!
+
+  FileDescriptor fileDescriptor;
+
+  nsAutoCString path;
+  nsresult rv = mURI->GetFilePath(path);
+  NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "GetFilePath failed!");
+
+  NS_UnescapeURL(path);
+
+  if (NS_SUCCEEDED(rv)) {
+    int fd = open(path.get(), O_RDONLY);
+    if (fd == -1) {
+      printf_stderr("RemoteOpenFileParent: file '%s' was not found!\n",
+                    path.get());
+    } else {
+      fileDescriptor = FileDescriptor(fd);
+    }
+  }
+
+  // Sending a potentially invalid file descriptor is just fine.
+  unused << Send__delete__(this, fileDescriptor);
+
+  if (fileDescriptor.IsValid()) {
+    // close file now that other process has it open, else we'll leak fds in the
+    // parent process.
+    close(fileDescriptor.PlatformHandle());
+  }
+
+#endif // OS_TYPE
+
+  return true;
+}
+
+} // namespace net
+} // namespace mozilla