The following enums duplicate declarations in presentation.mojom.

  enum PresentationConnectionState {
    CONNECTING,
    CONNECTED,
    CLOSED,
    TERMINATED
  };

  enum PresentationConnectionCloseReason {
    CONNECTION_ERROR,
    CLOSED,
    WENT_AWAY
  };

Since we are moving to use the Blink types as the canonical definitions for these, we should remove them once presentation.mojom is moved to the Blink public API.  Until that happens, some temporary conversion code will be necessary.