[Presentation API] (alternative) 1-UA: send message between controller and receiver page

third_party/WebKit/public/platform/modules/presentation/presentation.mojom

 // 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.
 
 // TODO(crbug.com/647290): Rename "Session" to "Connection"
 
 module blink.mojom;
 
 import "url/mojo/url.mojom";
 
@@ skipping 34 matching lines @@
 };
 
 struct SessionMessage {
   PresentationMessageType type;
   // Used when message type is TEXT.
   string? message;
   // Used when message type is ARRAY_BUFFER or BLOB.
   array<uint8>? data;
 };
 
+interface PresentationConnection {
+   // Called to set the PresentationConnection interface that sends
+   // messages in the opposite direction.
+   SetTargetConnection(PresentationConnection connection);
+
+   // Called when connection.send() is invoked at the other end of the
+   // connection.
+   OnSessionMessageReceived(SessionMessage message);
+};
+
 interface PresentationService {
   // Sets the PresentationServiceClient.
   SetClient(PresentationServiceClient client);
 
   // Called when the frame sets or changes the default presentation URLs.
   // When the default presentation is started on this frame,
   // PresentationServiceClient::OnDefaultSessionStarted will be invoked.
   SetDefaultPresentationUrls(array<url.mojom.Url> presentation_urls);
 
   // Starts listening for screen availability for presentation of
@@ skipping 37 matching lines @@
   CloseConnection(url.mojom.Url presentation_url, string presentation_id);
 
   // Called when terminate() is called by the frame.
   Terminate(url.mojom.Url presentation_url, string presentation_id);
 
   // Starts listening for messages for session with |sessionInfo|.
   // Messages will be received in
   // PresentationServiceClient::OnSessionMessagesReceived.
   // This is called after a presentation session is created.
   ListenForSessionMessages(PresentationSessionInfo sessionInfo);
+
+  SetPresentationConnection(PresentationSessionInfo sessionInfo,
+                            PresentationConnection connection);
 };
 
 interface PresentationServiceClient {
   // Called when the client tries to listen for screen availability changes for
   // presentation of |url| but it is not supported by the device or underlying
   // platform. This can also be called if the device is currently in a mode
   // where it can't do screen discoveries (eg. low battery).
   OnScreenAvailabilityNotSupported(url.mojom.Url url);
 
   // Called when the client is listening for screen availability for
@@ skipping 14 matching lines @@
                      string message);
 
   // See PresentationService::ListenForSessionMessages.
   OnSessionMessagesReceived(PresentationSessionInfo sessionInfo,
                             array<SessionMessage> messages);
 
   // See PresentationService::SetDefaultPresentationURL.
   OnDefaultSessionStarted(PresentationSessionInfo sessionInfo);
 
   // See PresentationService::ListeningForReceiverPageRendered.
-  OnReceiverConnectionAvailable(PresentationSessionInfo sessionInfo);
+  OnReceiverConnectionAvailable(PresentationSessionInfo sessionInfo,
+                                PresentationConnection connection);
 };