Set up decoder infrastructure

src/codecs/browser-png/decoder.ts

@@ -0,0 +1,15 @@
+import { canDecode, fileToBitmap } from '../../lib/util';
+
+export const name = 'Browser PNG Decoder';
+export const supportedExtensions = ['png'];
+export const supportedMimeTypes = ['image/png'];
+export async function decode(file: File): Promise<ImageBitmap> {
+  return fileToBitmap(file);
+}
+
+// tslint:disable-next-line:max-line-length It’s a data URL. Whatcha gonna do?
+const pngFile = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAC0lEQVQYV2NgAAIAAAUAAarVyFEAAAAASUVORK5CYII=';
+
+export function isSupported(): Promise<boolean> {
+  return canDecode(pngFile);
+}