Revert "Replace BundleFilter with RtpDemuxer in RtpTransport."

This reverts commit ea8b62a3e74fe91cd6bf66304839cd5677880a4e.

Reason for revert: Broke chromium tests.
Original change's description:
> Replace BundleFilter with RtpDemuxer in RtpTransport.
> 
> BundleFilter is replaced by RtpDemuxer in RtpTransport for payload
> type-based demuxing. RtpTransport will support MID-based demuxing later.
> 
> Each BaseChannel has its own RTP demuxing criteria and when connecting
> to the RtpTransport, BaseChannel will register itself as a demuxer sink.
> 
> The inheritance model is changed. New inheritance chain:
> DtlsSrtpTransport->SrtpTransport->RtpTranpsort
> 
> NOTE:
> When RTCP packets are received, Call::DeliverRtcp will be called for
> multiple times (webrtc:9035) which is an existing issue. With this CL,
> it will become more of a problem and should be fixed.
> 
> Bug: webrtc:8587
> Change-Id: I1d8a00443bd4bcbacc56e5e19b7294205cdc38f0
> Reviewed-on: https://webrtc-review.googlesource.com/61360
> Commit-Queue: Zhi Huang <zhihuang@webrtc.org>
> Reviewed-by: Steve Anton <steveanton@webrtc.org>
> Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#22613}

TBR=steveanton@webrtc.org,deadbeef@webrtc.org,zhihuang@webrtc.org

Change-Id: If245da9d1ce970ac8dab7f45015e9b268a5dbcbd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:8587
Reviewed-on: https://webrtc-review.googlesource.com/64860
Reviewed-by: Zhi Huang <zhihuang@webrtc.org>
Commit-Queue: Zhi Huang <zhihuang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22614}

pc/bundlefilter.h

@@ -0,0 +1,54 @@
+/*
+ *  Copyright 2004 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 PC_BUNDLEFILTER_H_
+#define PC_BUNDLEFILTER_H_
+
+#include <stdint.h>
+
+#include <set>
+#include <vector>
+
+#include "media/base/streamparams.h"
+#include "rtc_base/basictypes.h"
+
+namespace cricket {
+
+// In case of single RTP session and single transport channel, all session
+// (or media) channels share a common transport channel. Hence they all get
+// SignalReadPacket when packet received on transport channel. This requires
+// cricket::BaseChannel to know all the valid sources, else media channel
+// will decode invalid packets.
+//
+// This class determines whether a packet is destined for cricket::BaseChannel.
+// This is only to be used for RTP packets as RTCP packets are not filtered.
+// For RTP packets, this is decided based on the payload type.
+class BundleFilter {
+ public:
+  BundleFilter();
+  ~BundleFilter();
+
+  // Determines if a RTP packet belongs to valid cricket::BaseChannel.
+  bool DemuxPacket(const uint8_t* data, size_t len);
+
+  // Adds the supported payload type.
+  void AddPayloadType(int payload_type);
+
+  // Public for unittests.
+  bool FindPayloadType(int pl_type) const;
+  void ClearAllPayloadTypes();
+
+ private:
+  std::set<int> payload_types_;
+};
+
+}  // namespace cricket
+
+#endif  // PC_BUNDLEFILTER_H_