Reland of Add content type information to encoded images and corresponding rtp extension header

webrtc/modules/video_coding/include/video_coding_defines.h

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 43 matching lines @@
 
 struct VCMFrameCount {
   uint32_t numKeyFrames;
   uint32_t numDeltaFrames;
 };
 
 // Callback class used for passing decoded frames which are ready to be
 // rendered.
 class VCMReceiveCallback {
  public:
+  // TODO(ilnik): Once deprecation is complete, change this to pure virtual.
   virtual int32_t FrameToRender(VideoFrame& videoFrame,  // NOLINT
-                                rtc::Optional<uint8_t> qp) = 0;
+                                rtc::Optional<uint8_t> qp,
+                                VideoContentType /*content_type*/) {
+    return FrameToRender(videoFrame, qp);
+  }
+  // DEPRECATED. Use the other overloaded version.
+  virtual int32_t FrameToRender(VideoFrame& videoFrame,  // NOLINT
+                                rtc::Optional<uint8_t> qp) {
+    return -1;
+  }
   virtual int32_t ReceivedDecodedReferenceFrame(const uint64_t pictureId) {
     return -1;
   }
   // Called when the current receive codec changes.
   virtual void OnIncomingPayloadType(int payload_type) {}
   virtual void OnDecoderImplementationName(const char* implementation_name) {}
 
  protected:
   virtual ~VCMReceiveCallback() {}
 };
@@ skipping 79 matching lines @@
  public:
   virtual void RequestKeyFrame() = 0;
 
  protected:
   virtual ~KeyFrameRequestSender() {}
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_DEFINES_H_