[Presentation API] Change ListenForSessionMessages API to client-style.

content/public/browser/presentation_session_message.h

 // Copyright 2015 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 CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_MESSAGE_H_
 #define CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_MESSAGE_H_
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 enum PresentationMessageType {
   TEXT,
   ARRAY_BUFFER,
   BLOB,
 };
 
 // Represents a presentation session message.
 // If this is a text message, |data| is null; otherwise, |message| is null.
 // Empty messages are allowed.
 struct CONTENT_EXPORT PresentationSessionMessage {
  public:
+  explicit PresentationSessionMessage(PresentationMessageType type);
   ~PresentationSessionMessage();
 
-  // Creates string message, which takes the ownership of |message|.
-  static scoped_ptr<PresentationSessionMessage> CreateStringMessage(
-      const std::string& presentation_url,
-      const std::string& presentation_id,
-      scoped_ptr<std::string> message);
-
-  // Creates array buffer message, which takes the ownership of |data|.
-  static scoped_ptr<PresentationSessionMessage> CreateArrayBufferMessage(
-      const std::string& presentation_url,
-      const std::string& presentation_id,
-      scoped_ptr<std::vector<uint8_t>> data);
-
-  // Creates blob message, which takes the ownership of |data|.
-  static scoped_ptr<PresentationSessionMessage> CreateBlobMessage(
-      const std::string& presentation_url,
-      const std::string& presentation_id,
-      scoped_ptr<std::vector<uint8_t>> data);
-
   bool is_binary() const;
-  std::string presentation_url;
-  std::string presentation_id;
-  PresentationMessageType type;
-  scoped_ptr<std::string> message;
-  scoped_ptr<std::vector<uint8_t>> data;
-
- private:
-  PresentationSessionMessage(const std::string& presentation_url,
-                             const std::string& presentation_id,
-                             scoped_ptr<std::string> message);
-  PresentationSessionMessage(const std::string& presentation_url,
-                             const std::string& presentation_id,
-                             PresentationMessageType type,
-                             scoped_ptr<std::vector<uint8_t>> data);
+  const PresentationMessageType type;
+  std::string message;
+  std::vector<uint8_t> data;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_