add scrollToLine to the mockrenderer

- need implementation

lib/ace/test/mockrenderer.js

@@ -94,6 +94,9 @@ MockRenderer.prototype.updateCursor = function(position) {
     this.cursor.column = position.column;
 };
 
+MockRenderer.prototype.scrollToLine = function(row) {
+};
+
 MockRenderer.prototype.scrollCursorIntoView = function() {
     if (this.cursor.row < this.layerConfig.firstVisibleRow) {
         this.scrollToRow(this.cursor.row);