Round corners for Files.app's new ui.

chrome/browser/resources/file_manager/manifest_new_ui.json

 {
   // chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/
   "key": "MIGdMA0GCSqGSIb3DQEBAQUAA4GLADCBhwKBgQDlhpGghtnNJ7pluQN0RDwbUxwwi99oM35ZEaFYvxPLrf0fIEC18cfDdJi6u4aJ+UoSpgzK731L0P/k4LvK2Rz9kVKOy0+IvuRrWkT7lbrLfA1UEBh02OA1AAshjmyRg4IxCqgl8ia8XWq6HKegS1y1KXZYGgb4qp7Bh9VC4cIzswIBIw==",
   "manifest_version": 2,
   "name": "Files",
   "version": "3.0",
   "description": "File Manager",
   "incognito" : "split",
   "icons": {
     "16": "images/icon16.png",
     "128": "images/icon128.png"
   },
   "permissions": [
+    "experimental",
     "storage",
     "fileBrowserHandler",
     "fileBrowserPrivate",
     "fullscreen",
     "mediaPlayerPrivate",
     "mediaGalleriesPrivate",
     "metricsPrivate",
     "unlimitedStorage",
     // Comment out chrome:// permissions to debug on a desktop browser.
     "chrome://extension-icon/",
@@ skipping 169 matching lines @@
         "js/file_copy_manager.js",
         "js/path_util.js",
         "js/util.js",
         "js/test_util.js",
         "js/background.js"]
     },
     // chrome-extension://pmfjbimdmchhbnneeidfognadeopoehp is the image loader extension.
     "content_security_policy": "default-src 'none'; script-src 'self' chrome://resources chrome-extension://pmfjbimdmchhbnneeidfognadeopoehp; style-src 'self' 'unsafe-inline' chrome://resources; frame-src 'self' about:; img-src 'self' chrome://resources chrome://theme data: https://docs.google.com https://*.googleusercontent.com chrome://extension-icon; media-src 'self' https://*.googleusercontent.com; connect-src https://drive.google.com"
   }
 }