Implement ScopedFD in terms of ScopedGeneric.

base/files/scoped_file.cc

Index: base/files/scoped_file.cc
diff --git a/base/files/scoped_file.cc b/base/files/scoped_file.cc
new file mode 100644
index 0000000000000000000000000000000000000000..39f064de1c46e694f19c6de3800e3d44e9ca1c29
--- /dev/null
+++ b/base/files/scoped_file.cc
@@ -0,0 +1,35 @@
+// Copyright 2014 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/files/scoped_file.h"
+
+#include "base/logging.h"
+
+#if defined(OS_POSIX)
+#include <unistd.h>
+
+#include "base/posix/eintr_wrapper.h"
+#endif
+
+namespace base {
+namespace internal {
+
+#if defined(OS_POSIX)
+
+// static
+void ScopedFDCloseTraits::Free(int fd) {
+  // It's important to crash here.
+  // There are security implications to not closing a file descriptor
+  // properly. As file descriptors are "capabilities", keeping them open
+  // would make the current process keep access to a resource. Much of
+  // Chrome relies on being able to "drop" such access.
+  // It's especially problematic on Linux with the setuid sandbox, where
+  // a single open directory would bypass the entire security model.
+  PCHECK(0 == IGNORE_EINTR(close(fd)));
+}
+
+#endif  // OS_POSIX
+
+}  // namespace internal
+}  // namespace base