Extracting NetLog inner classes into their own classes.

net/log/net_log_parameters_callback.h

+// Copyright 2016 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.
+
+#ifndef NET_LOG_NET_LOG_PARAMETERS_CALLBACK_H_
+#define NET_LOG_NET_LOG_PARAMETERS_CALLBACK_H_
+
+#include <memory>
+
+#include "base/callback_forward.h"
+#include "net/log/net_log_capture_mode.h"
+
+namespace base {
+class Value;
+}
+
+namespace net {
+
+// A callback that returns a Value representation of the parameters
+// associated with an event.  If called, it will be called synchronously,
+// so it need not have owning references.  May be called more than once, or
+// not at all.  May return nullptr.
+typedef base::Callback<std::unique_ptr<base::Value>(NetLogCaptureMode)>
+    NetLogParametersCallback;
+
+}  // namespace net
+
+#endif  // NET_LOG_NET_LOG_PARAMETERS_CALLBACK_H_