Break ChannelIDSigner into two classes: ChannelIDKey and ChannelIDSource.

net/tools/quic/quic_client.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // A toy client, which connects to a specified port and sends QUIC
 // request to that endpoint.
 
 #ifndef NET_TOOLS_QUIC_QUIC_CLIENT_H_
 #define NET_TOOLS_QUIC_QUIC_CLIENT_H_
 
@@ skipping 134 matching lines @@
     server_id_ = server_id;
   }
 
   // SetProofVerifier sets the ProofVerifier that will be used to verify the
   // server's certificate and takes ownership of |verifier|.
   void SetProofVerifier(ProofVerifier* verifier) {
     // TODO(rtenneti): We should set ProofVerifier in QuicClientSession.
     crypto_config_.SetProofVerifier(verifier);
   }
 
-  // SetChannelIDSigner sets a ChannelIDSigner that will be called when the
-  // server supports channel IDs to sign a message proving possession of the
-  // given ChannelID. This object takes ownership of |signer|.
-  void SetChannelIDSigner(ChannelIDSigner* signer) {
-    crypto_config_.SetChannelIDSigner(signer);
+  // SetChannelIDSource sets a ChannelIDSource that will be called, when the
+  // server supports channel IDs, to obtain a channel ID for signing a message
+  // proving possession of the channel ID. This object takes ownership of
+  // |source|.
+  void SetChannelIDSource(ChannelIDSource* source) {
+    crypto_config_.SetChannelIDSource(source);
   }
 
   void SetSupportedVersions(const QuicVersionVector& versions) {
     supported_versions_ = versions;
   }
 
   // Takes ownership of the listener.
   void set_response_listener(ResponseListener* listener) {
     response_listener_.reset(listener);
   }
@@ skipping 79 matching lines @@
   // Size of initial flow control receive window to advertise to server.
   uint32 initial_flow_control_window_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicClient);
 };
 
 }  // namespace tools
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_CLIENT_H_