[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";
 
 struct PresentationSessionInfo {
   url.mojom.Url url;
   string id;
+  bool is_offscreen;
 };
 
 enum PresentationConnectionState {
   CONNECTING,
   CONNECTED,
   CLOSED,
   TERMINATED
 };
 
 enum PresentationConnectionCloseReason {
@@ skipping 21 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 {
+   // TODO(zhaobin): migrate SendSessionMessage from PresenationService =>
+   // PresentationConnection.Send(). http://crbug.com/658474
+
+   // Called to set the PresentationConnection that is the destination for
+   // messages sent and the source of messages received by this connection.
+   SetTargetConnection(PresentationConnection connection);
+
+   // Called when a message is sent by the target connection.
+   OnMessage(SessionMessage message);
+};
+
 interface PresentationService {
   // Sets the PresentationServiceClient.
   SetClient(PresentationServiceClient client);
 
+  /////////////Functions here are for the controller part of the API.///////////
+
   // 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
   // |availability_url|. Availability results will be returned to the client via
   // PresentationServiceClient::OnScreenAvailabilityUpdated.
   ListenForScreenAvailability(url.mojom.Url availability_url);
 
@@ skipping 14 matching lines @@
   StartSession(array<url.mojom.Url> presentation_urls)
       => (PresentationSessionInfo? sessionInfo, PresentationError? error);
 
   // Called when joinSession() is called by the frame. The result callback
   // works the same as for the method above. JoinSession will join a known
   // session (i.e. when the page navigates or the user opens another tab)
   // silently and without user action.
   JoinSession(array<url.mojom.Url> presentation_urls, string? presentation_id)
       => (PresentationSessionInfo? sessionInfo, PresentationError? error);
 
+  // Called in StartSession's callback function for 1-UA presentations only. It
+  // sends controlling frame's PresentationConnection to PresentationService.
+  SetPresentationConnection(PresentationSessionInfo sessionInfo,
+                            PresentationConnection connection);
+
+  //////////////////////////////////////////////////////////////////////////////
+
   // Called when send() is called by the frame. The true in the
   // result callback notifies that the service is ready for next message.
   // The false in the result callback notifies the renderer to stop sending
   // the send requests and invalidate all pending requests. This occurs
   // for eg., when frame is deleted or navigated away.
   SendSessionMessage(PresentationSessionInfo sessionInfo,
                      SessionMessage message_request) => (bool success);
 
   // Called when close() is called by the frame.
   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);
 };
 
 interface PresentationServiceClient {
+
+  ////////////Functions here are called only on the controlling page.///////////
+
   // 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
   // presentation of |url| and the state changes. When the client starts to
   // listen for screen availability, this method will always be called to give
   // the current known state. It will then be called to notify of state updates.
   OnScreenAvailabilityUpdated(url.mojom.Url url, bool available);
 
+  // See PresentationService::SetDefaultPresentationURL.
+  OnDefaultSessionStarted(PresentationSessionInfo sessionInfo);
+
+  //////////////////////////////////////////////////////////////////////////////
+
   // Called when the state of PresentationConnection |connection| started on
   // this frame has changed to |newState|.
   OnConnectionStateChanged(PresentationSessionInfo connection,
                            PresentationConnectionState newState);
 
   // Caled when the state of |connection| started on this frame has changed to
   // CLOSED.
   OnConnectionClosed(PresentationSessionInfo connection,
                      PresentationConnectionCloseReason reason,
                      string message);
 
   // See PresentationService::ListenForSessionMessages.
   OnSessionMessagesReceived(PresentationSessionInfo sessionInfo,
                             array<SessionMessage> messages);
 
-  // See PresentationService::SetDefaultPresentationURL.
-  OnDefaultSessionStarted(PresentationSessionInfo sessionInfo);
-
-  // See PresentationService::ListeningForReceiverPageRendered.
-  OnReceiverConnectionAvailable(PresentationSessionInfo sessionInfo);
+  // Called on a presentation receiver when the first presentation connection is
+  // available from the controlling page.
+  OnReceiverConnectionAvailable(PresentationSessionInfo sessionInfo,
+                                PresentationConnection connection);
 };