Add memory consumption treemap tab

Summary: There are some issues with label positioning, but overall works.

Reviewed By: defHLT

Differential Revision: D29588329

fbshipit-source-id: 5c2e8f6f139d997559111fa2ad124ae1d695b36a

desktop/plugins/public/fresco/ImagePool.tsx

@@ -7,9 +7,7 @@
  * @format
  */
 
-import {ImageId, ImageData} from './api';
-
-export type ImagesMap = {[imageId in ImageId]: ImageData};
+import {ImageId, ImageData, ImagesMap} from './api';
 
 const maxInflightRequests = 10;