Build WebRTC with data channel only.

webrtc/logging/rtc_event_log/rtc_event_log_factory.h

Index: webrtc/logging/rtc_event_log/rtc_event_log_factory.h
diff --git a/webrtc/logging/rtc_event_log/rtc_event_log_factory.h b/webrtc/logging/rtc_event_log/rtc_event_log_factory.h
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index 0000000000000000000000000000000000000000..53a18c656b2adfb87129cf1e89055d883614bc30
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+/*
+ *  Copyright 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.
+ */
+
+#ifndef WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_FACTORY_H_
+#define WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_FACTORY_H_
+
+#include <memory>
+
+#include "webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h"
+
+namespace webrtc {
+
+class RtcEventLogFactory : public RtcEventLogFactoryInterface {
+ public:
+  ~RtcEventLogFactory() override {}
+
+  std::unique_ptr<RtcEventLog> CreateRtcEventLog() override;
+};
+
+std::unique_ptr<RtcEventLogFactoryInterface> CreateRtcEventLogFactory();
+}  // namespace webrtc
+
+#endif  // WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_FACTORY_H_