Fix compilation if HAVE_WEBRTC_VIDEO is not defined.

talk/media/webrtc/nullwebrtcvideoengine.h

 /*
  * libjingle
- * Copyright 2011 Google Inc.
+ * Copyright 2016 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
  *     this list of conditions and the following disclaimer in the documentation
  *     and/or other materials provided with the distribution.
  *  3. The name of the author may not be used to endorse or promote products
  *     derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef TALK_MEDIA_WEBRTCMEDIAENGINE_H_
-#define TALK_MEDIA_WEBRTCMEDIAENGINE_H_
+#ifndef TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_
+#define TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_
 
-#include <string>
 #include <vector>
 
+#include "talk/media/base/mediachannel.h"
 #include "talk/media/base/mediaengine.h"
-#include "webrtc/config.h"
 
 namespace webrtc {
-class AudioDeviceModule;
-}
-namespace cricket {
-class WebRtcVideoDecoderFactory;
-class WebRtcVideoEncoderFactory;
-}
+
+class Call;
+
+}  // namespace webrtc
+
 
 namespace cricket {
 
-class WebRtcMediaEngineFactory {
+class VideoMediaChannel;
+class WebRtcVideoDecoderFactory;
+class WebRtcVideoEncoderFactory;
+
+// Video engine implementation that does nothing and can be used in
+// CompositeMediaEngine.
+class NullWebRtcVideoEngine {
  public:
-  static MediaEngineInterface* Create(
-      webrtc::AudioDeviceModule* adm,
-      WebRtcVideoEncoderFactory* encoder_factory,
-      WebRtcVideoDecoderFactory* decoder_factory);
+  NullWebRtcVideoEngine() {}
+  ~NullWebRtcVideoEngine() {}
+
+  void SetExternalDecoderFactory(WebRtcVideoDecoderFactory* decoder_factory) {}
+  void SetExternalEncoderFactory(WebRtcVideoEncoderFactory* encoder_factory) {}
+
+  void Init() {}
+
+  const std::vector<VideoCodec>& codecs() {
+    return codecs_;
+  }
+
+  RtpCapabilities GetCapabilities() {
+    RtpCapabilities capabilities;
+    return capabilities;
+  }
+
+  VideoMediaChannel* CreateChannel(webrtc::Call* call,
+      const VideoOptions& options) {
+    return nullptr;
+  }
+
+ private:
+  std::vector<VideoCodec> codecs_;
 };
 
-// Verify that extension IDs are within 1-byte extension range and are not
-// overlapping.
-bool ValidateRtpExtensions(const std::vector<RtpHeaderExtension>& extensions);
-
-// Convert cricket::RtpHeaderExtension:s to webrtc::RtpExtension:s, discarding
-// any extensions not validated by the 'supported' predicate. Duplicate
-// extensions are removed if 'filter_redundant_extensions' is set, and also any
-// mutually exclusive extensions (see implementation for details).
-std::vector<webrtc::RtpExtension> FilterRtpExtensions(
-    const std::vector<RtpHeaderExtension>& extensions,
-    bool (*supported)(const std::string&),
-    bool filter_redundant_extensions);
-
 }  // namespace cricket
 
-#endif  // TALK_MEDIA_WEBRTCMEDIAENGINE_H_
+#endif  // TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_