Add a new GetTlsUniqueChannelBinding method to SSLSocket, and implement nss version.

net/socket/ssl_client_socket_mac.h

Index: net/socket/ssl_client_socket_mac.h
diff --git a/net/socket/ssl_client_socket_mac.h b/net/socket/ssl_client_socket_mac.h
index d7ced4549ddca0b293efaf8345b5a5ceec8911cf..67994aa05e7e58672364e2b8e21aae0207ef8548 100644
--- a/net/socket/ssl_client_socket_mac.h
+++ b/net/socket/ssl_client_socket_mac.h
@@ -39,14 +39,19 @@ class SSLClientSocketMac : public SSLClientSocket {
                      const SSLClientSocketContext& context);
   virtual ~SSLClientSocketMac();
 
-  // SSLClientSocket implementation.
-  virtual void GetSSLCertRequestInfo(
-      SSLCertRequestInfo* cert_request_info) OVERRIDE;
+  // SSLSocket implementation.
   virtual int ExportKeyingMaterial(const base::StringPiece& label,
                                    bool has_context,
                                    const base::StringPiece& context,
                                    unsigned char* out,
                                    unsigned int outlen) OVERRIDE;
+  virtual int GetTlsUniqueChannelBinding(unsigned char* out,
+                                         unsigned int *outlen,
+                                         unsigned int outlen_max) OVERRIDE;
+
+  // SSLClientSocket implementation.
+  virtual void GetSSLCertRequestInfo(
+      SSLCertRequestInfo* cert_request_info) OVERRIDE;
   virtual NextProtoStatus GetNextProto(std::string* proto,
                                        std::string* server_protos) OVERRIDE;
   virtual ServerBoundCertService* GetServerBoundCertService() const OVERRIDE;