Revert of Moving MediaStreamSignaling logic into PeerConnection.

talk/app/webrtc/datachannel.h

Index: talk/app/webrtc/datachannel.h
diff --git a/talk/app/webrtc/datachannel.h b/talk/app/webrtc/datachannel.h
index 2713ae3b553ed7a79f32de9f34a214c3396e1877..4506f71b146c71f95ab22a04fbcffca97b43bb32 100644
--- a/talk/app/webrtc/datachannel.h
+++ b/talk/app/webrtc/datachannel.h
@@ -29,7 +29,6 @@
 #define TALK_APP_WEBRTC_DATACHANNEL_H_
 
 #include <deque>
-#include <set>
 #include <string>
 
 #include "talk/app/webrtc/datachannelinterface.h"
@@ -82,28 +81,6 @@
   }
 
   OpenHandshakeRole open_handshake_role;
-};
-
-// Helper class to allocate unique IDs for SCTP DataChannels
-class SctpSidAllocator {
- public:
-  // Gets the first unused odd/even id based on the DTLS role. If |role| is
-  // SSL_CLIENT, the allocated id starts from 0 and takes even numbers;
-  // otherwise, the id starts from 1 and takes odd numbers.
-  // Returns false if no id can be allocated.
-  bool AllocateSid(rtc::SSLRole role, int* sid);
-
-  // Attempts to reserve a specific sid. Returns false if it's unavailable.
-  bool ReserveSid(int sid);
-
-  // Indicates that |sid| isn't in use any more, and is thus available again.
-  void ReleaseSid(int sid);
-
- private:
-  // Checks if |sid| is available to be assigned to a new SCTP data channel.
-  bool IsSidAvailable(int sid) const;
-
-  std::set<int> used_sids_;
 };
 
 // DataChannel is a an implementation of the DataChannelInterface based on
@@ -152,6 +129,9 @@
   // rtc::MessageHandler override.
   virtual void OnMessage(rtc::Message* msg);
 
+  // Called if the underlying data engine is closing.
+  void OnDataEngineClose();
+
   // Called when the channel's ready to use.  That can happen when the
   // underlying DataMediaChannel becomes ready, or when this channel is a new
   // stream on an existing DataMediaChannel, and we've finished negotiation.
@@ -161,7 +141,6 @@
   void OnDataReceived(cricket::DataChannel* channel,
                       const cricket::ReceiveDataParams& params,
                       const rtc::Buffer& payload);
-  void OnStreamClosedRemotely(uint32_t sid);
 
   // The remote peer request that this channel should be closed.
   void RemotePeerRequestClose();
@@ -172,10 +151,7 @@
   // be called once.
   void SetSctpSid(int sid);
   // Called when the transport channel is created.
-  // Only needs to be called for SCTP data channels.
   void OnTransportChannelCreated();
-  // Called when the transport channel is destroyed.
-  void OnTransportChannelDestroyed();
 
   // The following methods are for RTP only.
 
@@ -190,11 +166,6 @@
   cricket::DataChannelType data_channel_type() const {
     return data_channel_type_;
   }
-
-  // Emitted when state transitions to kClosed.
-  // In the case of SCTP channels, this signal can be used to tell when the
-  // channel's sid is free.
-  sigslot::signal1<DataChannel*> SignalClosed;
 
  protected:
   DataChannel(DataChannelProviderInterface* client,
@@ -276,6 +247,16 @@
   PacketQueue queued_send_data_;
 };
 
+class DataChannelFactory {
+ public:
+  virtual rtc::scoped_refptr<DataChannel> CreateDataChannel(
+      const std::string& label,
+      const InternalDataChannelInit* config) = 0;
+
+ protected:
+  virtual ~DataChannelFactory() {}
+};
+
 // Define proxy for DataChannelInterface.
 BEGIN_PROXY_MAP(DataChannel)
   PROXY_METHOD1(void, RegisterObserver, DataChannelObserver*)