Convert shim to Typescript (#32)

ext/src/shim/cast/classes/SessionRequest.ts

@@ -0,0 +1,17 @@
+"use strict";
+
+import { Capability } from "../enums";
+import { requestSession } from "../../timeout";
+
+// https://developers.google.com/cast/docs/reference/chrome/chrome.cast.SessionRequest
+export default class SessionRequest {
+    public language: string = null;
+    public dialRequest: any = null;
+
+    constructor (
+            public appId: string
+          , public capabilities = [
+                Capability.VIDEO_OUT
+              , Capability.AUDIO_OUT ]
+          , public requestSessionTimeout: number = requestSession) {}
+};