Relanding: Allow the DTLS fingerprint verification to occur after the handshake.

webrtc/p2p/base/dtlstransportchannel.h

Index: webrtc/p2p/base/dtlstransportchannel.h
diff --git a/webrtc/p2p/base/dtlstransportchannel.h b/webrtc/p2p/base/dtlstransportchannel.h
index 7b8247a44903a5da6ac3535845f6f83a8c9678be..32b4a3fd48d3cfaa329f64a1d1f5fd0f54f96719 100644
--- a/webrtc/p2p/base/dtlstransportchannel.h
+++ b/webrtc/p2p/base/dtlstransportchannel.h
@@ -196,8 +196,12 @@ class DtlsTransportChannelWrapper : public TransportChannelImpl {
   // Needed by DtlsTransport.
   TransportChannelImpl* channel() { return channel_; }
 
+  // For informational purposes. Tells if the DTLS handshake has finished.
+  // This may be true even if writable() is false, if the remote fingerprint
+  // has not yet been verified.
+  bool IsDtlsConnected();
+
  private:
-  void OnReadableState(TransportChannel* channel);
   void OnWritableState(TransportChannel* channel);
   void OnReadPacket(TransportChannel* channel, const char* data, size_t size,
                     const rtc::PacketTime& packet_time, int flags);