Removes fallback from Prefs to LoadExtension on UI thread

chrome/test/data/extensions/good/Preferences

 {
    "extensions": {
       "settings": {
          "behllobkkfkfnphdnhnkndlbkcpglgmj": {
             "location": 1,
             "path": "behllobkkfkfnphdnhnkndlbkcpglgmj/1.0.0.0",
-            "state": 1
+            "state": 1,
+            "manifest": {
+              "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDuUZGKCDbff6IRaxa4Pue7PPkxwPaNhGT3JEqppEsNWFjM80imEdqMbf3lrWqEfaHgaNku7nlpwPO1mu3/4Hr+XdNa5MhfnOnuPee4hyTLwOs3Vzz81wpbdzUxZSi2OmqMyI5oTaBYICfNHLwcuc65N5dbt6WKGeKgTpp4v7j7zwIDAQAB",
+              "version": "1.0.0.0",
+              "name": "My extension 1",
+              "description": "The first extension that I made.",
+              "icons": {
+                "128": "icon_128.png"
+              },
+              "default_locale": "en_US",
+              "toolstrips": [
+                {
+                  "path": "toolstrip1.html",
+                  "mole": "lorem_ipsum.html",
+                  "mole_height": 200
+                },
+                "toolstrip2.html"
+              ],
+              "background_page": "backgroundpage.html",
+              "permissions": ["tabs", "http://*.google.com/*", "https://*.google.com/*"],
+              "content_scripts": [
+                {
+                  "matches": ["file://*", "http://*.google.com/*", "https://*.google.com/*"],
+                  "js": ["script1.js", "script2.js"],
+                  "css": ["style1.css", "style2.css", "style2.css"]
+                },
+                {
+                  "matches": ["http://*.news.com/*"],
+                  "js": ["js_files/script3.js"]
+                }
+              ],
+              "privacy_blacklists": ["blacklist.pbl"]
+            }
          },
          "bjafgdebaacbbbecmhlhpofkepfkgcpa": {
             "location": 1,
             "path": "bjafgdebaacbbbecmhlhpofkepfkgcpa/1.0",
-            "state": 1
+            "state": 1,
+            "manifest": {
+              "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDRS2GUBOUAO5VZ2CMRId/eRR8/e9V42nUvY5XG+0sZ+JDHEjIQdq8qQy7HqdqEpCXKPMSPuMiC2t2HE9/hpL89SblNn3mwYPtSJGQdZvAzuv6SB0oA6jZ66V7+h/k0noGD3Tcu+Ko/vfkt5wCx2uHVK29k5JR/vGr0klaoVezGlwIDAQAB",
+              "version": "1.0",
+              "name": "My extension 3",
+              "toolstrips": ["toolstrip.html"],
+              "permissions": ["tabs"],
+              "content_scripts": [
+                {
+                  "matches": ["file://*"],
+                  "js": ["page.js"]
+                }
+              ]
+            }
          },
          "hpiknbiabeeppbpihjehijgoemciehgk": {
             "location": 1,
             "path": "hpiknbiabeeppbpihjehijgoemciehgk/2",
-            "state": 1
+            "state": 1,
+            "manifest": {
+              "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC1nrgIE4OIQez0DVtc3JPR5O69s0XrH7TYC/xUC2e7Cla6eZldsA1PCWzLacimqtwfu7ljGXslk0HffkWNNou28Ip07KIC5oQHGEieAkNdPd3Pfi7QcAz+D0/xNPxuMtTKyuptWNtb2TTWD0MG7IdLHbMYFO6avkZtP+ldiKqxOwIDAQAB",
+              "version": "2",
+              "name": "My extension 2",
+              "plugins": [
+                { "path": "content_plugin.dll", "public": true },
+                { "path": "extension_plugin.dll" }
+              ],
+              "background_page": "background.html"
+            }
          }
       }
    }
 }