Make chrome.alarms API accept non-integers and too-short delays.

chrome/common/extensions/docs/examples/api/eventPage/basic/manifest.json

 {
   "name": "Event Page Example",
   "description": "Demonstrates usage and features of the event page",
   "version": "1.0",
   "manifest_version": 2,
-  "permissions": ["alarms", "tabs", "bookmarks", "experimental", "keybinding", "http://*.google.com/*"],
+  "permissions": ["alarms", "tabs", "bookmarks", "declarativeWebRequest", "*://*.google.com/*"],
   "background": {
     "scripts": ["background.js"],
     "persistent": false
   },
   "browser_action": {
     "default_icon" : "icon.png",
     "default_title": "Start Event Page"
   },
   "commands": {
     "open-google": {
       "description": "Open a tab to google.com",
       "suggested_key": { "default": "Ctrl+Shift+L" }
     },
     "_execute_browser_action": {
       "suggested_key": { "default": "Ctrl+Shift+K" }
     }
   }
 }