[Presentation API / Media Router] Clean up default pres URL logic.

content/common/presentation/presentation_service.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.
 
 module presentation;
 
 struct PresentationSessionInfo {
   string url;
   string id;
 };
@@ skipping 23 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 PresentationService {
-  // Called when the frame sets or changes the default presentation URL.
-  SetDefaultPresentationURL(string url);
-
   // Sets the PresentationServiceClient.
   SetClient(PresentationServiceClient client);
 
+  // Called when the frame sets or changes the default presentation URL.
+  // When the default presentation is started on this frame,
+  // PresentationServiceClient::OnDefaultSessionStarted will be invoked.
+  SetDefaultPresentationURL(string url);
+
   // Starts listening for screen availability for presentation of
   // |url|. Availability results will be returned to the client via
   // PresentationServiceClient::OnScreenAvailabilityUpdated.
   ListenForScreenAvailability(string url);
 
   // Stops listening for screen availability for the presentation of |url|. The
   // PresentationServiceClient will stop receiving availability updates for
   // |url|.
   StopListeningForScreenAvailability(string url);
 
-  // Called when the renderer is ready to receive the browser initiated
-  // session. If the default session is started by the embedder before this
-  // call, the embedder may queue it and run the callback when the call is
-  // performed.
-  ListenForDefaultSessionStart()
-      => (PresentationSessionInfo? defaultSessionInfo);
-
   // Called when startSession() is called by the frame. The result callback
   // will return a non-null and valid PresentationSessionInfo if starting the
   // session succeeded, or null with a PresentationError if starting the
   // session failed.
   // The presentation id returned in |sessionInfo| on success is generated by
   // the UA.
   // If the UA identifies a matching session (same presentation url), the user
   // may choose this existing session and the page will join it rather than get
   // a new one.
   StartSession(string presentation_url)
       => (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(string presentation_url, string? presentation_id)
       => (PresentationSessionInfo? sessionInfo, PresentationError? error);
 
   // 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);
+  SendSessionMessage(PresentationSessionInfo sessionInfo,
+                     SessionMessage message_request) => (bool success);
 
   // Called when closeSession() is called by the frame.
   CloseSession(string presentation_url, string presentation_id);
 
   // Starts listening for state changes for sessions created on this frame.
   // When state change occurs, PresentationServiceClient::OnSessionStateChanged
   // will be invoked with the session and its new state.
   // This is called after a presentation session is created.
   ListenForSessionStateChange();
 
@@ skipping 15 matching lines @@
   // 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(string url, bool available);
 
   // See PresentationService::ListenForSessionStateChange.
   OnSessionStateChanged(PresentationSessionInfo sessionInfo,
                         PresentationSessionState newState);
 
   // See PresentationService::ListenForSessionMessages.
-  OnSessionMessagesReceived(PresentationSessionInfo sessionInfo, array<SessionMessage> messages);
+  OnSessionMessagesReceived(PresentationSessionInfo sessionInfo,
+                            array<SessionMessage> messages);
+
+  // See PresentationService::SetDefaultPresentationURL.
+  OnDefaultSessionStarted(PresentationSessionInfo sessionInfo);
 };