Add an experimental permissions API for extensions.

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 1042 matching lines @@
         "name": "onFocusChanged",
         "type": "function",
         "description": "Fired when the currently focused window changes. Will be chrome.windows.WINDOW_ID_NONE if all chrome windows have lost focus. Note: On some Linux window managers, WINDOW_ID_NONE will always be sent immediately preceding a switch from one chrome window to another.",
         "parameters": [
           {"type": "integer", "name": "windowId", "minimum": 0, "description": "ID of the newly focused window."}
         ]
       }
     ]
   },
   {
+    "namespace": "experimental.permissions",
+    "types": [
+      {
+        "id": "Permissions",
+        "type": "object",
+        "properties": {
+          "permissions": {
+            "type": "array",
+            "items": {"type": "string"},
+            "optional": true,
+            "description": "List of named permissions (does not include hosts or origins)."
+          }
+        }
+      }
+    ],
+    "events": [
+      {
+        "name": "onAdded",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Fired when the extension acquires new permissions.",
+        "parameters": [
+          {
+            "$ref": "Permissions",
+            "name": "permissions",
+            "description": "The newly acquired permissions."
+          }
+        ]
+      },
+      {
+        "name": "onRemoved",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Fired when access to permissions has been removed from the extension.",
+        "parameters": [
+          {
+            "$ref": "Permissions",
+            "name": "permissions",
+            "description": "The permissions that have been removed."
+          }
+        ]
+      }
+     ],
+    "functions": [
+      {
+        "name": "getAll",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Gets the extension's current set of permissions.",
+        "parameters": [
+          {
+            "name": "callback",
+            "type": "function",
+            "parameters": [
+               {
+                "name": "permissions",
+                "$ref": "Permissions",
+                "description": "The extension's active permissions."
+              }
+            ]
+          }
+        ]
+      },
+      {
+        "name": "contains",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Checks if the extension has the specified permissions.",
+        "parameters": [
+          {
+            "name": "permissions",
+            "$ref": "Permissions"
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "parameters": [
+              {
+                "name": "result",
+                "type": "boolean",
+                "description": "True if the extension has the specified permissions."
+              }
+            ]
+          }
+        ]
+      },
+      {
+        "name": "request",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Requests access to the specified permissions. These permissions must be defined in the optional_permissions field of the manifest.",
+        "parameters": [
+          {
+            "name": "permissions",
+            "$ref": "Permissions"
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "granted",
+                "type": "boolean",
+                "description": "True if the user granted the specified permissions."
+              }
+            ]
+          }
+        ]
+      },
+      {
+        "name": "remove",
+        "type": "function",
+        "unprivileged": true,
+        "description": "Removes access to the specified permissions.",
+        "parameters": [
+          {
+            "name": "permissions",
+            "$ref": "Permissions"
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "removed",
+                "type": "boolean",
+                "description": "True if the permissions were removed."
+              }
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  {
     "namespace": "tabs",
     "types": [
       {
         "id": "Tab",
         "type": "object",
         "properties": {
           "id": {"type": "integer", "minimum": 0, "description": "The ID of the tab. Tab IDs are unique within a browser session."},
           "index": {"type": "integer", "minimum": 0, "description": "The zero-based index of the tab within its window."},
           "windowId": {"type": "integer", "minimum": 0, "description": "The ID of the window the tab is contained within."},
           "selected": {"type": "boolean", "description": "Whether the tab is selected."},
@@ skipping 5305 matching lines @@
             "name": "details",
             "properties": {
               "extensionId": {
                 "type": "string",
                 "optional": true,
                 "description": "An optional id to do notifications for an app other than the calling app. This is just to allow prototyping with an extension that sends notifications on behalf of apps that don't support notifications yet; this will be removed before the API becomes stable."
               },
               "title": {
                 "type": "string",
                 "optional": true,
-                "description": "The title of the notification."  
+                "description": "The title of the notification."
               },
               "bodyText": {
                 "type": "string",
                 "optional": true,
                 "description": "The text content of the notification."
               },
               "linkUrl": {
                 "type": "string",
                 "optional": true,
                 "description": "The URL for an optional link to show along with the notification. If you specify a linkUrl, you must also specify a value for linkText."
@@ skipping 146 matching lines @@
                 "description": "A string result code. The value is non-empty on success only in tests.",
                 "optional": "true"
               }
             ]
           }
         ]
       }
     ]
   }
 ]