Gallery.app: Replace the existing gallery with the new separated gallery.

ui/file_manager/gallery/manifest.json

 {
   // chrome-extension://nlkncpkkdoccmpiclbokaimcnedabhhm/
   "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1hFTC+sl9e4ufs6ccGhspbgnMQb3GMikA/QwghFVp00WDwFu7no8xIOWJwY9lFQP+NrbSsze3JL9Wg6FmHC6xKIncwZJKwyDDd2g+9/gEZLn5Ar1piPyf+ELtuX+m0Pjp0l2+rVMz2UiP5OUvFqvmCZqJJQnTVjRut3IMjDP6npb5HyDTgqlPgNHWmsLAQZZKTyYfqswBFkvmwiSHTNJuxkh+i1hxo2m8RcBQsXWL8Mt9+WPl0uABIZc7UvLoZwNz1pAKWb5sv0y4oBugpw4ZVIvCT/pxplLXF35GGBNWAkgimkpYu+SldoZQV8SZW1kUSIcrpYW80mA7KxfK5H8vwIDAQAB",
   "manifest_version": 2,
   "name": "Gallery",
   "version": "2.0",
   "description": "Picture and video browser app.",
   "display_in_launcher": false,
   "incognito" : "split",
   "icons": {
     "16": "images/100/icon.png",
     "32": "images/200/icon.png"
   },
   "permissions": [
     "fileSystem",
     "fileBrowserHandler",
     "fileBrowserPrivate",
     "fullscreen",
     "mediaPlayerPrivate",
     "metricsPrivate",
     "storage",
     "chrome://extension-icon/",
     "chrome://resources/",
     "chrome://theme/",
     "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj"
   ],
   "file_handlers": {
-    "video": {
+    "image": {
       "types": [
         "image/*"
       ],
       "extensions": [
         "bmp",
         "gif",
         "ico",
         "jpg",
         "jpeg",
         "png",
         "webp"
       ],
       // TODO(hirono): Rename and localize this.
-      "title": "Open in new Gallery"
+      "title": "Open"
     }
   },
   "app": {
     "background": {
       "scripts": [
         "chrome://resources/js/cr.js",
         "chrome://resources/js/cr/event_target.js",
         "chrome://resources/js/cr/ui/array_data_model.js",
         "chrome://resources/js/load_time_data.js",
         // util.js and async_util.js should be included before volume_manager.js.
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/common/js/util.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/common/js/async_util.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/common/js/path_util.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/common/js/volume_manager_common.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/volume_manager.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/test_util.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/common/js/error_util.js",
         "chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/foreground/js/file_type.js",
         "js/background.js"
       ]
     },
     "content_security_policy": "default-src 'none'; script-src 'self' chrome://resources chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj; style-src 'self' 'unsafe-inline'; img-src 'self' chrome://resources chrome://theme data: https://*.googleusercontent.com chrome://extension-icon; media-src 'self'; object-src 'self';"
   }
 }