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

chrome/browser/media/router/mojo/media_router.mojom

Index: chrome/browser/media/router/mojo/media_router.mojom
diff --git a/chrome/browser/media/router/mojo/media_router.mojom b/chrome/browser/media/router/mojo/media_router.mojom
index 37fc064748de40d2a68f17ebec05798d2c3a4871..3aa60c0088a23fa44650591a7ced49586510ac73 100644
--- a/chrome/browser/media/router/mojo/media_router.mojom
+++ b/chrome/browser/media/router/mojo/media_router.mojom
@@ -4,6 +4,8 @@
 
 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";
 
@@ -38,8 +40,7 @@ struct MediaRoute {
   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;
@@ -322,6 +323,25 @@ interface MediaRouteProvider {
               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