Avatar defaults and colors

ts/window.d.ts

@@ -135,12 +135,27 @@ type ConfirmationDialogViewProps = {
   resolve: () => void;
 };
 
+// This is the subset of `window.FontFace` that we need. We should delete this after
+//   upgrading to TypeScript 4.4, which will include a full declaration in [its official
+//   DOM type definitions][0].
+//
+// [0]: https://github.com/microsoft/TypeScript/blob/03dff41c9f2038f66fb358e5c23ebd7271145978/lib/lib.dom.d.ts#L5343-L5364
+declare class FontFace {
+  constructor(
+    family: string,
+    source: string | ArrayBuffer | ArrayBufferView,
+    descriptors?: unknown
+  );
+  load(): Promise<FontFace>;
+}
+
 declare global {
   // We want to extend `window`'s properties, so we need an interface.
   // eslint-disable-next-line no-restricted-syntax
   interface Window {
     startApp: () => void;
 
+    FontFace: typeof FontFace;
     _: typeof Underscore;
     $: typeof jQuery;
 
@@ -339,6 +354,9 @@ declare global {
         readDraftData: any;
         saveAttachmentToDisk: any;
         writeNewDraftData: any;
+        deleteAvatar: (path: string) => Promise<void>;
+        getAbsoluteAvatarPath: (src: string) => string;
+        writeNewAvatarData: (data: ArrayBuffer) => Promise<string>;
       };
       Types: {
         Attachment: typeof Attachment;