Use manifest version 2 for font settings sample extension.

chrome/common/extensions/docs/samples.json

 {
   "api": {
     "chrome.alarms.clear": "alarms.html#method-clear",
     "chrome.alarms.clearAll": "alarms.html#method-clearAll",
     "chrome.alarms.create": "alarms.html#method-create",
     "chrome.alarms.get": "alarms.html#method-get",
     "chrome.alarms.getAll": "alarms.html#method-getAll",
     "chrome.alarms.onAlarm": "alarms.html#event-onAlarm",
     "chrome.app.window.create": "app.window.html#method-create",
     "chrome.app.window.focus": "app.window.html#method-focus",
@@ skipping 1233 matching lines @@
         "chrome.fontSettings.onMinimumFontSizeChanged",
         "chrome.fontSettings.setDefaultFixedFontSize",
         "chrome.fontSettings.setDefaultFontSize",
         "chrome.fontSettings.setFont",
         "chrome.fontSettings.setMinimumFontSize"
       ],
       "crx_path": null,
       "description": "Sample extension for Font Settings API",
       "features": [
         "browser_action",
-        "fontSettings",
-        "popup"
+        "fontSettings"
       ],
       "icon": "fonts128.png",
       "id": "31d10fd5e61ca51eb59073b358d4ab5267cbf318",
       "name": "Font Settings",
       "packaged_app": false,
       "path": "examples/api/fontSettings/",
       "protocols": [],
-      "search_string": "FONT SETTINGS SAMPLE EXTENSION FOR FONT SETTINGS API BROWSER_ACTION FONTSETTINGS POPUP CHROME.FONTSETTINGS.CLEARDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.CLEARDEFAULTFONTSIZE CHROME.FONTSETTINGS.CLEARFONT CHROME.FONTSETTINGS.CLEARMINIMUMFONTSIZE CHROME.FONTSETTINGS.GETDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.GETDEFAULTFONTSIZE CHROME.FONTSETTINGS.GETFONT CHROME.FONTSETTINGS.GETFONTLIST CHROME.FONTSETTINGS.GETMINIMUMFONTSIZE CHROME.FONTSETTINGS.ONDEFAULTFIXEDFONTSIZECHANGED CHROME.FONTSETTINGS.ONDEFAULTFONTSIZECHANGED CHROME.FONTSETTINGS.ONFONTCHANGED CHROME.FONTSETTINGS.ONMINIMUMFONTSIZECHANGED CHROME.FONTSETTINGS.SETDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.SETDEFAULTFONTSIZE CHROME.FONTSETTINGS.SETFONT CHROME.FONTSETTINGS.SETMINIMUMFONTSIZE",
+      "search_string": "FONT SETTINGS SAMPLE EXTENSION FOR FONT SETTINGS API BROWSER_ACTION FONTSETTINGS CHROME.FONTSETTINGS.CLEARDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.CLEARDEFAULTFONTSIZE CHROME.FONTSETTINGS.CLEARFONT CHROME.FONTSETTINGS.CLEARMINIMUMFONTSIZE CHROME.FONTSETTINGS.GETDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.GETDEFAULTFONTSIZE CHROME.FONTSETTINGS.GETFONT CHROME.FONTSETTINGS.GETFONTLIST CHROME.FONTSETTINGS.GETMINIMUMFONTSIZE CHROME.FONTSETTINGS.ONDEFAULTFIXEDFONTSIZECHANGED CHROME.FONTSETTINGS.ONDEFAULTFONTSIZECHANGED CHROME.FONTSETTINGS.ONFONTCHANGED CHROME.FONTSETTINGS.ONMINIMUMFONTSIZECHANGED CHROME.FONTSETTINGS.SETDEFAULTFIXEDFONTSIZE CHROME.FONTSETTINGS.SETDEFAULTFONTSIZE CHROME.FONTSETTINGS.SETFONT CHROME.FONTSETTINGS.SETMINIMUMFONTSIZE",
       "source_files": [
         "manifest.json",
         "popup.html",
         "popup.js"
       ],
-      "source_hash": "02a9aac2ea6ab8095d0b53a1b8433fcc354133f6",
+      "source_hash": "d46eaac64f67efa4d433b8589605effb50b99795",
       "zip_path": "examples/api/fontSettings.zip"
     },
     {
       "api_calls": [
         "chrome.browserAction.onClicked",
         "chrome.browserAction.setBadgeBackgroundColor",
         "chrome.browserAction.setBadgeText",
         "chrome.browserAction.setIcon",
         "chrome.browserAction.setTitle",
         "chrome.extension.getBackgroundPage",
@@ skipping 1534 matching lines @@
         "manifest.json",
         "popup.html",
         "popup.js",
         "sample.css"
       ],
       "source_hash": "8e51dc3a9577065d22ce92f3c838edc5ceaf4e65",
       "zip_path": "examples/api/extension/isAllowedAccess.zip"
     }
   ]
 }