Adding callbacks to `chrome.cookies.{set,remove}`.

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 3277 matching lines @@
               "url": {"type": "string", "description": "The request-URI to associate with the setting of the cookie. This value can affect the default domain and path values of the created cookie. If host permissions for this URL are not specified in the manifest file, the API call will fail."},
               "name": {"type": "string", "optional": true, "description": "The name of the cookie. Empty by default if omitted."},
               "value": {"type": "string", "optional": true, "description": "The value of the cookie. Empty by default if omitted."},
               "domain": {"type": "string", "optional": true, "description": "The domain of the cookie. If omitted, the cookie becomes a host-only cookie."},
               "path": {"type": "string", "optional": true, "description": "The path of the cookie. Defaults to the path portion of the url parameter."},
               "secure": {"type": "boolean", "optional": true, "description": "Whether the cookie should be marked as Secure. Defaults to false."},
               "httpOnly": {"type": "boolean", "optional": true, "description": "Whether the cookie should be marked as HttpOnly. Defaults to false."},
               "expirationDate": {"type": "number", "optional": true, "description": "The expiration date of the cookie as the number of seconds since the UNIX epoch. If omitted, the cookie becomes a session cookie."},
               "storeId": {"type": "string", "optional": true, "description": "The ID of the cookie store in which to set the cookie. By default, the cookie is set in the current execution context's cookie store."}
             }
+          },
+          {
+            "type": "function",
+            "name": "callback",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "cookie", "$ref": "Cookie", "optional": true, "description": "Contains details about the cookie that's been set.  If setting failed for any reason, this will be \"null\", and \"chrome.extension.lastError\" will be set."
+              }
+            ]
           }
         ]
       },
       {
         "name": "remove",
         "type": "function",
         "description": "Deletes a cookie by name.",
         "parameters": [
           {
             "type": "object",
             "name": "details",
             "description": "Information to identify the cookie to remove.",
             "properties": {
               "url": {"type": "string", "description": "The URL associated with the cookie. If host permissions for this URL are not specified in the manifest file, the API call will fail."},
               "name": {"type": "string", "description": "The name of the cookie to remove."},
               "storeId": {"type": "string", "optional": true, "description": "The ID of the cookie store to look in for the cookie. If unspecified, the cookie is looked for by default in the current execution context's cookie store."}
             }
+          },
+          {
+            "type": "function",
+            "name": "callback",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "details",
+                "type": "object",
+                "description": "Contains details about the cookie that's been removed.  If removal failed for any reason, this will be \"null\", and \"chrome.extension.lastError\" will be set.",
+                "optional": true,
+                "properties": {
+                  "url": {"type": "string", "description": "The URL associated with the cookie that's been removed."},
+                  "name": {"type": "string", "description": "The name of the cookie that's been removed."},
+                  "storeId": {"type": "string", "description": "The ID of the cookie store from which the cookie was removed."}
+                }
+              }
+            ]
           }
         ]
       },
       {
         "name": "getAllCookieStores",
         "type": "function",
         "description": "Lists all existing cookie stores.",
         "parameters": [
           {
             "type": "function",
@@ skipping 1207 matching lines @@
                   "token": { "type": "string", "optional": true }
                 }
               }
             ]
           }
         ]
       }
     ]
   }
 ]