[fuchsia] Remove the unused ApplicationControllerReceiver API.

Bug: 1028409
Change-Id: Id289aa7a7c8c708bb6a530d3ebf6f5be4cb8deb2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2130266
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755254}

fuchsia/fidl/cast/application_controller.fidl

@@ -4,14 +4,6 @@
 
 library chromium.cast;
 
-// TODO(crbug.com/1028409): Remove this interface and use ApplicationContext.
-[Discoverable]
-protocol ApplicationControllerReceiver {
-  /// Used by the Agent to receive a controller from the Cast Runner.
-  /// Can only be called at most one time for the lifetime of the Component.
-  SetApplicationController(ApplicationController controller);
-};
-
 /// Allows clients to access and modify certain aspects of the Cast receiver
 /// application runtime.
 protocol ApplicationController {