Remove URLRequestStatus mutators and introduce FromError.

net/url_request/url_request_status.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 "net/url_request/url_request_status.h"
+
+#include "net/base/net_errors.h"
+
+namespace net {
+
+URLRequestStatus URLRequestStatus::FromError(int error) {
+  if (error == OK) {
+    return URLRequestStatus(SUCCESS, OK);
+  } else if (error == ERR_IO_PENDING) {
+    return URLRequestStatus(IO_PENDING, ERR_IO_PENDING);
+  } else if (error == ERR_ABORTED) {
+    return URLRequestStatus(CANCELED, ERR_ABORTED);
+  } else {
+    return URLRequestStatus(FAILED, error);
+  }
+}
+
+}  // namespace net