Add an experimental permissions API for extensions.

chrome/common/extensions/docs/samples.json

 {
   "api": {
     "chrome.bookmarks.create": "bookmarks.html#method-create",
     "chrome.bookmarks.export": "bookmarks.html#method-export",
     "chrome.bookmarks.get": "bookmarks.html#method-get",
     "chrome.bookmarks.getChildren": "bookmarks.html#method-getChildren",
     "chrome.bookmarks.getRecent": "bookmarks.html#method-getRecent",
     "chrome.bookmarks.getSubTree": "bookmarks.html#method-getSubTree",
     "chrome.bookmarks.getTree": "bookmarks.html#method-getTree",
     "chrome.bookmarks.import": "bookmarks.html#method-import",
@@ skipping 116 matching lines @@
     "chrome.omnibox.onInputEntered": "omnibox.html#event-onInputEntered",
     "chrome.omnibox.onInputStarted": "omnibox.html#event-onInputStarted",
     "chrome.omnibox.sendSuggestions": "omnibox.html#method-sendSuggestions",
     "chrome.omnibox.setDefaultSuggestion": "omnibox.html#method-setDefaultSuggestion",
     "chrome.pageAction.hide": "pageAction.html#method-hide",
     "chrome.pageAction.onClicked": "pageAction.html#event-onClicked",
     "chrome.pageAction.setIcon": "pageAction.html#method-setIcon",
     "chrome.pageAction.setPopup": "pageAction.html#method-setPopup",
     "chrome.pageAction.setTitle": "pageAction.html#method-setTitle",
     "chrome.pageAction.show": "pageAction.html#method-show",
+    "chrome.permissions.contains": "permissions.html#method-contains",
+    "chrome.permissions.getAll": "permissions.html#method-getAll",
+    "chrome.permissions.onAdded": "permissions.html#event-onAdded",
+    "chrome.permissions.onRemoved": "permissions.html#event-onRemoved",
+    "chrome.permissions.remove": "permissions.html#method-remove",
+    "chrome.permissions.request": "permissions.html#method-request",
     "chrome.proxy.onProxyError": "proxy.html#event-onProxyError",
     "chrome.tabs.captureVisibleTab": "tabs.html#method-captureVisibleTab",
     "chrome.tabs.connect": "tabs.html#method-connect",
     "chrome.tabs.create": "tabs.html#method-create",
     "chrome.tabs.detectLanguage": "tabs.html#method-detectLanguage",
     "chrome.tabs.executeScript": "tabs.html#method-executeScript",
     "chrome.tabs.get": "tabs.html#method-get",
     "chrome.tabs.getAllInWindow": "tabs.html#method-getAllInWindow",
     "chrome.tabs.getCurrent": "tabs.html#method-getCurrent",
     "chrome.tabs.getSelected": "tabs.html#method-getSelected",
@@ skipping 1732 matching lines @@
       "source_files": [
         "manifest.json",
         "popup.html",
         "sample.css"
       ],
       "source_hash": "c8bfc2b60f25c24dc3c5aaf75dd635c9419df66d",
       "zip_path": "examples\/api\/extension\/isAllowedAccess.zip"
     }
   ]
 }