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

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

Index: third_party/WebKit/public/platform/modules/presentation/presentation.mojom
diff --git a/third_party/WebKit/public/platform/modules/presentation/presentation.mojom b/third_party/WebKit/public/platform/modules/presentation/presentation.mojom
index 0427db2c60e7d0709b13a1b4b2bbbeea73563084..ebb776d96a021a67cffc275214cf3d3fa9e5ee21 100644
--- a/third_party/WebKit/public/platform/modules/presentation/presentation.mojom
+++ b/third_party/WebKit/public/platform/modules/presentation/presentation.mojom
@@ -11,6 +11,7 @@ import "url/mojo/url.mojom";
 struct PresentationSessionInfo {
   url.mojom.Url url;
   string id;
+  bool is_offscreen;
 };
 
 enum PresentationConnectionState {
@@ -52,10 +53,24 @@ struct SessionMessage {
   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.
@@ -90,6 +105,13 @@ interface PresentationService {
   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
@@ -112,6 +134,9 @@ interface PresentationService {
 };
 
 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
@@ -124,6 +149,11 @@ interface PresentationServiceClient {
   // 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,
@@ -139,9 +169,8 @@ interface PresentationServiceClient {
   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);
 };