refactor!: rename _getIndexLevel to __getRowLevel to accept a row (#9952)

Author: vursen

packages/grid/src/vaadin-grid-data-provider-mixin.js

@@ -181,6 +181,12 @@ export const DataProviderMixin = (superClass) =>
       this.requestContentUpdate();
     }
 
+    /** @private */
+    __getRowLevel(row) {
+      const { level } = this._dataProviderController.getFlatIndexContext(row.index);
+      return level;
+    }
+
     /** @private */
     __getRowItem(row) {
       const { item } = this._dataProviderController.getFlatIndexContext(row.index);
@@ -254,16 +260,6 @@ export const DataProviderMixin = (superClass) =>
       }
     }
 
-    /**
-     * @param {number} index
-     * @return {number}
-     * @protected
-     */
-    _getIndexLevel(index = 0) {
-      const { level } = this._dataProviderController.getFlatIndexContext(index);
-      return level;
-    }
-
     /** @protected */
     _onDataProviderPageRequested() {
       this._setLoading(true);

packages/grid/src/vaadin-grid-mixin.js

@@ -840,7 +840,7 @@ export const GridMixin = (superClass) =>
       return {
         index: row.index,
         item: row._item,
-        level: this._getIndexLevel(row.index),
+        level: this.__getRowLevel(row),
         expanded: this._isExpanded(row._item),
         selected: this._isSelected(row._item),
         detailsOpened: !!this.rowDetailsRenderer && this._isDetailsOpened(row._item),