[MediaRouter] Replace RouteMessage with PresentationConnectionMessage

content/public/common/presentation_connection_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_COMMON_PRESENTATION_CONNECTION_MESSAGE_H_
 #define CONTENT_PUBLIC_COMMON_PRESENTATION_CONNECTION_MESSAGE_H_
 
 #include <stddef.h>  // For size_t
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/optional.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // The maximum number of bytes allowed in a presentation connection message.
 CONTENT_EXPORT extern const size_t kMaxPresentationConnectionMessageSize;
 
 // Represents a presentation connection message.  If this is a text message,
 // |data| is null; otherwise, |message| is null.  Empty messages are allowed.
 struct CONTENT_EXPORT PresentationConnectionMessage {
  public:
   // Constructs a new, untyped message (for Mojo).  These messages are not valid
   // and exactly one of |message| or |data| must be set.
   PresentationConnectionMessage();
-  // PCM is a move-only type.
-  PresentationConnectionMessage(PresentationConnectionMessage&& other);
+  // Copy constructor / assignment are necessary due to MediaRouter allowing
+  // multiple RouteMessageObserver instances per MediaRoute.
+  PresentationConnectionMessage(const PresentationConnectionMessage& other);
+  PresentationConnectionMessage(PresentationConnectionMessage&& other) noexcept;
   // Constructs a text message from |message|.
   explicit PresentationConnectionMessage(std::string message);
   // Constructs a binary message from |data|.
   explicit PresentationConnectionMessage(std::vector<uint8_t> data);
+
   ~PresentationConnectionMessage();
 
   bool is_binary() const;
 
   bool operator==(const PresentationConnectionMessage& other) const;
   PresentationConnectionMessage& operator=(
+      const PresentationConnectionMessage& other);
+  PresentationConnectionMessage& operator=(
       PresentationConnectionMessage&& other);
 
   base::Optional<std::string> message;
   base::Optional<std::vector<uint8_t>> data;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_PRESENTATION_CONNECTION_MESSAGE_H_