lib/Ext/ComponentQuery.js
function(component, selector) {
            if (!selector) {
                return true;
            }
            var query = this.cache[selector];
            if (!query) {
                this.cache[selector] = query = this.parse(selector);
            }
            return query.is(component);
        }
function(component, selector) {
            if (!selector) {
                return true;
            }
            var query = this.cache[selector];
            if (!query) {
                this.cache[selector] = query = this.parse(selector);
            }
            return query.is(component);
        }
Tests whether the passed Component matches the selector string.
@param {Ext.Component} component The Component to test.
@param {String} selector The selector string to test against.
@return {Boolean} `true` if the Component matches the selector.
@member Ext.ComponentQuery