[EasyUnlock] Fixing the setup connection finder and message format.

components/cryptauth/wire_message.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_CRYPTAUTH_WIRE_MESSAGE_H_
 #define COMPONENTS_CRYPTAUTH_WIRE_MESSAGE_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 
 namespace cryptauth {
 
 class WireMessage {
  public:
   // Creates a WireMessage containing |payload| for feature |feature|.
   explicit WireMessage(const std::string& payload, const std::string& feature);
+
+  // Creates a WireMessage containing |body| (a serialized JSON) as the message
+  // body.
+  explicit WireMessage(const std::string& body);

[Tim Song, 2017/04/28 05:32:20]

I think it's cleaner to subclass WireMessage (i.e. SetupWireMessage) like you
did for the ConnectionFinder.

[sacomoto, 2017/04/28 06:59:01]

Discussed offline.

+
   virtual ~WireMessage();
 
   // Returns the deserialized message from |serialized_message|, or nullptr if
   // the message is malformed. Sets |is_incomplete_message| to true if the
   // message does not have enough data to parse the header, or if the message
   // length encoded in the message header exceeds the size of the
   // |serialized_message|.
   static std::unique_ptr<WireMessage> Deserialize(
       const std::string& serialized_message,
       bool* is_incomplete_message);
 
   // Returns a serialized representation of |this| message.
   virtual std::string Serialize() const;
 
   const std::string& payload() const { return payload_; }
   const std::string& feature() const { return feature_; }
+  const std::string& body() const { return body_; }
 
  private:
   // The message payload.
   const std::string payload_;
 
   // The feature which sends or intends to receive this message (e.g.,
   // EasyUnlock).
   const std::string feature_;
 
+  // The message body. When this is set |payload_| and |feature_| are empty, and
+  // vice-versa.
+  const std::string body_;
+
   DISALLOW_COPY_AND_ASSIGN(WireMessage);
 };
 
 }  // namespace cryptauth
 
 #endif  // COMPONENTS_CRYPTAUTH_WIRE_MESSAGE_H_