Build WebRTC with data channel only.

webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h

Index: webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h
diff --git a/webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h b/webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h
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index 0000000000000000000000000000000000000000..e3b7a67f1eed3742bff52c4650fa64c3ac508a2d
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+++ b/webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h
@@ -0,0 +1,34 @@
+/*
+ *  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_INTERFACE_H_
+#define WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_FACTORY_INTERFACE_H_
+
+#include <memory>
+
+#include "webrtc/logging/rtc_event_log/rtc_event_log.h"
+
+namespace webrtc {
+
+// This interface exists to allow webrtc to be optionally built without
+// RtcEventLog support. A PeerConnectionFactory is constructed with an
+// RtcEventLogFactoryInterface, which may or may not be null.
+class RtcEventLogFactoryInterface {
+ public:
+  virtual ~RtcEventLogFactoryInterface() {}
+
+  virtual std::unique_ptr<RtcEventLog> CreateRtcEventLog() = 0;
+};
+
+std::unique_ptr<RtcEventLogFactoryInterface> CreateRtcEventLogFactory();
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_FACTORY_INTERFACE_H_