[Media Router] Add a supports_web_ui_controller attribute to MediaRoute

chrome/common/media_router/mojo/media_router.mojom

Index: chrome/common/media_router/mojo/media_router.mojom
diff --git a/chrome/common/media_router/mojo/media_router.mojom b/chrome/common/media_router/mojo/media_router.mojom
index d339c5c7931f13aef17d31cd66ad78e49a299266..20ff03771469c106283548fcb29ac03aa1e26a4a 100644
--- a/chrome/common/media_router/mojo/media_router.mojom
+++ b/chrome/common/media_router/mojo/media_router.mojom
@@ -88,8 +88,11 @@ struct MediaRoute {
   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.
+  // well as its own route controls within an extensionview in the media router

[imcheng, 2017/06/16 00:12:32]

s/media router/Media Router

[takumif, 2017/06/16 18:16:53]

Done.

+  // dialog.
   string? custom_controller_path;
+  // Whether the provider for this route supports WebUI route controllers.
+  bool supports_web_ui_controller;

[imcheng, 2017/06/16 00:12:32]

per discussion: supports_media_route_controller makes more sense and is more
future-proof.

[takumif, 2017/06/16 18:16:53]

Done. In WebUIMessageHandler and JS, I think it's okay to say WebUI route
controller.

   // 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.