Convert wallpaper picker to v2 app

chrome/browser/resources/chromeos/wallpaper_manager/manifest.json

Index: chrome/browser/resources/chromeos/wallpaper_manager/manifest.json
diff --git a/chrome/browser/resources/chromeos/wallpaper_manager/manifest.json b/chrome/browser/resources/chromeos/wallpaper_manager/manifest.json
index c39971efb02e74bcd65795c91a7e27714216f576..fbad7e1230b90f74f198f6880ff902c48861d164 100644
--- a/chrome/browser/resources/chromeos/wallpaper_manager/manifest.json
+++ b/chrome/browser/resources/chromeos/wallpaper_manager/manifest.json
@@ -5,26 +5,16 @@
   "version": "0.1",
   "manifest_version": 2,
   "description": "An experimental wallpaper picker UI",
-  "chrome_url_overrides": {
-    "wallpapers": "main.html"
-  },
   "permissions": [
     "wallpaperPrivate",
     "tabs",
-    "webRequest",
-    "http://lh5.ggpht.com/",
     "https://commondatastorage.googleapis.com/",
     "https://storage.googleapis.com/"
   ],
   "app": {
-    "launch": {
-      "container": "panel",
-      "width": 550,
-      "height": 440,
-      "local_path": "main.html"
+    "background": {
+      "scripts": ["js/event_page.js"]
     }
   },
-  "content_security_policy":
-    "default-src:none; object-src 'none'; script-src 'self'",
   "display_in_launcher": false
 }