Update chrome.management.getAll() API externs
chrome.management.getAll() incorrectly set the return type as an array of extensions,
but the API doesn't actually return anything directly.  Update it to mark it as returning
undefined.
@@ -4028,7 +4028,7 @@ chrome.management.InstallOptions;
/**
* @param {function(!Array<!ExtensionInfo>): void=} opt_callback Optional
* callback function.
- * @return {!Array<!ExtensionInfo>}
+ * @return {undefined}
*/
chrome.management.getAll = function(opt_callback) {};
