[Presentation API] Additional plumbing for PresentationServiceImpl.

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;
 
 import "presentation_session.mojom";
 
 struct PresentationSessionInfo {
-    PresentationSession session;
     string url;
     string id;
 };
 
 enum PresentationErrorType {
     NO_AVAILABLE_SCREENS,
     SESSION_REQUEST_CANCELLED,
     NO_PRESENTATION_FOUND,
     UNKNOWN,
 };
 
 struct PresentationError {
-    PresentationErrorType errorType;
+    PresentationErrorType error_type;
     string message;
 };
 
 interface PresentationService {
+    // Called when the browser parses the specified default presentation URL or
+    // presentation ID.
+    SetDefaultPresentationUrl(
+        string default_presentation_url,
+        string? default_presentation_id);
+
     // Returns the last screen availability state if it’s changed since the last
     // time the method was called. The client has to call this method again when
     // handling the result (provided via Mojo callback) to get the next update
     // about the availability status.
     // May start discovery of the presentation screens. The implementation might
     // stop discovery once there are no active calls to GetScreenAvailability.
     // |presentation_url| can be specified to help the implementation to filter
     // out incompatible screens.
-    GetScreenAvailability(string? presentation_url) => (bool available);
+    GetScreenAvailability(string? presentation_url) =>
+        (string? presentation_url, bool available);
 
     // Called when the frame no longer listens to the
     // |availablechange| event.
-    OnScreenAvailabilityListenerRemoved();
+    OnScreenAvailabilityListenerRemoved(string? presentation_url);
 
     // 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 is always returned along with the initialized
     // session on success.
     // If the UA identifies a matching session (same presentation url and id),
     // the user may choose this existing session and the page will join it
     // rather than get a new one. An empty presentation id means that the
     // UA will generate the presentation id.
     StartSession(string presentation_url, string? presentation_id)
-         => (PresentationSessionInfo? sessionInfo, PresentationError? error);
+        => (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);
-};
+};