新品到着优化 review by 孙凯

@@ -37,7 +37,6 @@ export default class NewArrival extends React.PureComponent {
         this.renderSectionHeader = this.renderSectionHeader.bind(this);
         this._onPressProductFilter = this._onPressProductFilter.bind(this);
         this._renderHeader = this._renderHeader.bind(this);
-        this._shouldItemUpdate = this._shouldItemUpdate.bind(this);
         this.renderItem = this.renderItem.bind(this);
 
         this.state = {