Loosening the coupling between WebRTC and //third_party/protobuf

webrtc/base/protobuf_utils.h

+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <string>
+
+#ifndef WEBRTC_BASE_PROTOBUF_UTILS_H_
+#define WEBRTC_BASE_PROTOBUF_UTILS_H_
+
+typedef std::string ProtoString;

[kwiberg-webrtc, 2017/03/22 10:03:22]

using ProtoString = std::string;

How are you making sure that no one uses std::string instead of this alias?

[mbonadei, 2017/03/23 16:13:58]

Done.

+
+#ifdef WEBRTC_ENABLE_PROTOBUF

[kwiberg-webrtc, 2017/03/22 10:03:22]

When adding new preprocessor define, please always set it to 1 for enable and 0
for disable, and test it with #if instead of #ifdef; that way, the compiler
(which uses -Wundef) will warn you if you forget to set the define in build
targets that need it.

[mbonadei, 2017/03/23 16:13:58]

Done and thanks for pointing this out. I was not aware of this.

+
+#include "third_party/protobuf/src/google/protobuf/message_lite.h"
+#include "third_party/protobuf/src/google/protobuf/repeated_field.h"
+
+using google::protobuf::MessageLite;
+using google::protobuf::RepeatedPtrField;
+
+#endif  // WEBRTC_ENABLE_PROTOBUF
+
+#endif  // WEBRTC_BASE_PROTOBUF_UTILS_H_

[kwiberg-webrtc, 2017/03/22 10:03:22]

The things in this header are put in the root namespace. Why not put them in
e.g. namespace webrtc?