Adding "adapter" ORTC objects on top of ChannelManager/BaseChannel/etc.

webrtc/ortc/rtpparametersconversion.h

Index: webrtc/ortc/rtpparametersconversion.h
diff --git a/webrtc/ortc/rtpparametersconversion.h b/webrtc/ortc/rtpparametersconversion.h
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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_ORTC_RTPPARAMETERSCONVERSION_H_
+#define WEBRTC_ORTC_RTPPARAMETERSCONVERSION_H_
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/api/rtcerror.h"
+#include "webrtc/api/rtpparameters.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/pc/mediasession.h"
+#include "webrtc/media/base/codec.h"
+
+namespace webrtc {
+
+// NOTE: Some functions are templated for convenience, such that template-based
+// code dealing with AudioContentDescription and VideoContentDescription can
+// use this easily. Such methods are usable with cricket::AudioCodec and
+// cricket::VideoCodec.
+
+//***************************************************************************
+// Functions for converting from new webrtc:: structures to old cricket::
+// structures.
+//
+// As the return values imply, all of these functions do validation of the
+// parameters and return an error if they're invalid. It's expected that any
+// default values (such as video clock rate of 90000) have been filled by the
+// time the webrtc:: structure is being converted to the cricket:: one.
+//
+// These are expected to be used when parameters are passed into an RtpSender
+// or RtpReceiver, and need to be validated and converted so they can be
+// applied to the media engine level.
+//***************************************************************************
+
+// Returns error on invalid input. Certain message types are only valid for
+// certain feedback types.
+RTCErrorOr<cricket::FeedbackParam> ToCricketFeedbackParam(
+    const RtcpFeedback& feedback);
+
+// Verifies that the codec kind is correct, and it has mandatory parameters
+// filled, with values in valid ranges.
+template <typename C>
+RTCErrorOr<C> ToCricketCodec(const RtpCodecParameters& codec);
+
+// Verifies that payload types aren't duplicated, in addition to normal
+// validation.
+template <typename C>
+RTCErrorOr<std::vector<C>> ToCricketCodecs(
+    const std::vector<RtpCodecParameters>& codecs);
+
+// Validates that header extension IDs aren't duplicated.
+RTCErrorOr<cricket::RtpHeaderExtensions> ToCricketRtpHeaderExtensions(
+    const std::vector<RtpHeaderExtensionParameters>& extensions);
+
+// SSRCs are allowed to be ommitted. This may be used for receive parameters
+// where SSRCs are unsignaled.
+RTCErrorOr<cricket::StreamParamsVec> ToCricketStreamParamsVec(
+    const std::vector<RtpEncodingParameters>& encodings);
+
+//*****************************************************************************
+// Functions for converting from old cricket:: structures to new webrtc::
+// structures. Unlike the above functions, these are permissive with regards to
+// input validation; it's assumed that any necessary validation already
+// occurred.
+//
+// These are expected to be used either to convert from audio/video engine
+// capabilities to RtpCapabilities, or to convert from already-parsed SDP
+// (in the form of cricket:: structures) to webrtc:: structures. The latter
+// functionality is not yet implemented.
+//*****************************************************************************
+
+// Returns empty value if |cricket_feedback| is a feedback type not
+// supported/recognized.
+rtc::Optional<RtcpFeedback> ToRtcpFeedback(
+    const cricket::FeedbackParam& cricket_feedback);
+
+template <typename C>
+RtpCodecCapability ToRtpCodecCapability(const C& cricket_codec);
+
+template <class C>
+RtpCapabilities ToRtpCapabilities(
+    const std::vector<C>& cricket_codecs,
+    const cricket::RtpHeaderExtensions& cricket_extensions);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_ORTC_RTPPARAMETERSCONVERSION_H_