[Media Router] Custom Controls 1 - Add MediaStatus, MediaRouteController, and mojo interfaces

chrome/browser/media/router/mojo/media_router.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 media_router.mojom;
 
+import "chrome/browser/media/router/mojo/media_controller.mojom";
+import "chrome/browser/media/router/mojo/media_status.mojom";
 import "mojo/common/time.mojom";
 import "url/mojo/origin.mojom";
 
 // Represents an output sink to which media can be routed.
 struct MediaSink {
   enum IconType {
     CAST,
     CAST_AUDIO,
     CAST_AUDIO_GROUP,
     GENERIC,
@@ skipping 14 matching lines @@
 
 // Should be kept in sync with media_route.h.
 struct MediaRoute {
   // The ID of this media route, e.g. "r_PR1O_blkC9dsKp-tb1ti8qurOo".
   string media_route_id;
   // The ID of the media source being sent through this media route.
   // May be missing if route is not local.
   string? media_source;
   // The ID of sink that is rendering the media content.
   string media_sink_id;
-  // Human readable description of this route, e.g.
-  // "Tab casting".
+  // Human readable description of this route, e.g. "Tab casting".
   string description;
   // Specifies that the route is requested locally.
   bool is_local;
   // An optional path to an HTML page bundled bundled with the media router
   // component extension. When set, the route can have custom route detail as
   // well as its own route controls in the media router dialog.
   string? custom_controller_path;
   // Set to true if this route should be displayed for |media_sink_id| in UI.
   bool for_display;
   // Set to true if this route was created by an incognito profile.
@@ skipping 262 matching lines @@
   // Indicates that the Media Router is interested in finding a sink that
   // matches |search_criteria| and is compatible with the source urn
   // |media_source|. |search_criteria| should contain an exact copy of the user
   // input. The user's current domain is also used to search.  The domain is the
   // hosted domain of the user's signed-in identity, or empty if the user has no
   // domain or is not signed in.
   SearchSinks(string sink_id,
               string media_source,
               SinkSearchCriteria search_criteria) =>
                   (string sink_id);
+
+  // Creates a controller for the media route with given |route_id| and binds it
+  // to |media_controller| for receiving media commands. This method returns
+  // false if such a media route doesn't exist, a controller already exists
+  // for it, or there was an error while creating a controller.
+  // |media_controller| becomes invalid when the media route is terminated. The
+  // created controller is destroyed when |media_controller| becomes invalid.
+  // TODO(takumif): Consider returning an enum instead of a bool to distinguish
+  // between error conditions for metrics/debugging.
+  CreateMediaRouteController(string route_id,
+                             MediaController& media_controller) =>
+                                 (bool success);
+
+  // Sets the observer to be notified whenever there is a change in the status
+  // of a media route. A media route can have at most one observer at a time,
+  // and it will be overwritten each time this method is called with the same
+  // |route_id|.
+  // TODO(takumif): Consider allowing multiple observers per media route.
+  SetMediaRouteStatusObserver(string route_id, MediaStatusObserver observer);

[dcheng, 2017/03/08 01:08:20]

Is there a time when we'd want to create a media router without an observer?
Since this is 1:1 atm, we should just bind it as part
CreateMediaRouteController() by passing MediaStatusObserver.

[takumif, 2017/03/08 04:24:03]

We originally had it that way and there was some discussion about it in the
previous CL [1]. We gravitated towards having two separate methods because the
MediaController implementation and the provider that MediaStatusObserver
observes don't really have to be the same object.

[1] https://codereview.chromium.org/2674363002/

[mark a. foltz, 2017/03/13 18:22:31]

The context might have been support for multiple observers of the same
controller - but it looks like that's left as a TODO.

Can you deep link to the comment thread where this was discussed so I can
refresh myself?

 };
 
 // Interface for a service which observes state changes across media
 // sources, sinks, and issues.
 interface MediaRouter {
 
   // Represents overall media sink availability states.
   // UNAVAILABLE - No sinks are available.
   // PER_SOURCE - Sinks are available, but are only compatible with specific
   //              media sources.
@@ skipping 55 matching lines @@
 
   // Called when the a batch of messages arrives from the media sink for the
   // route given by |route_id|.
   // |StartListeningForRouteMessages| must be called first in order to receive
   // messages.
   // |route_id|: ID of route of the messages.
   // |messages|: A non-empty list of messages received.
   OnRouteMessagesReceived(string route_id,
                           array<RouteMessage> messages);
 };