Add Electron IPC APIs for authenticated media

src/@types/global.d.ts

@@ -33,7 +33,9 @@ type ElectronChannel =
     | "update-downloaded"
     | "userDownloadCompleted"
     | "userDownloadAction"
-    | "openDesktopCapturerSourcePicker";
+    | "openDesktopCapturerSourcePicker"
+    | "userAccessToken"
+    | "serverSupportedVersions";
 
 declare global {
     interface Window {

src/vector/platform/ElectronPlatform.tsx

@@ -44,6 +44,7 @@ import { UPDATE_EVENT } from "matrix-react-sdk/src/stores/AsyncStore";
 import { avatarUrlForRoom, getInitialLetter } from "matrix-react-sdk/src/Avatar";
 import DesktopCapturerSourcePicker from "matrix-react-sdk/src/components/views/elements/DesktopCapturerSourcePicker";
 import { OidcRegistrationClientMetadata } from "matrix-js-sdk/src/matrix";
+import { MatrixClientPeg } from "matrix-react-sdk/src/MatrixClientPeg";
 
 import VectorBasePlatform from "./VectorBasePlatform";
 import { SeshatIndexManager } from "./SeshatIndexManager";
@@ -127,6 +128,19 @@ export default class ElectronPlatform extends VectorBasePlatform {
             });
         });
 
+        // `userAccessToken` (IPC) is requested by the main process when appending authentication
+        // to media downloads. A reply is sent over the same channel.
+        window.electron.on("userAccessToken", () => {
+            window.electron!.send("userAccessToken", MatrixClientPeg.get()?.getAccessToken());
+        });
+
+        // `serverSupportedVersions` is requested by the main process when it needs to know if the
+        // server supports a particular version. This is primarily used to detect authenticated media
+        // support. A reply is sent over the same channel.
+        window.electron.on("serverSupportedVersions", async () => {
+            window.electron!.send("serverSupportedVersions", await MatrixClientPeg.get()?.getVersions());
+        });
+
         // try to flush the rageshake logs to indexeddb before quit.
         window.electron.on("before-quit", function () {
             logger.log("element-desktop closing");