fix(cdk/tree): fix build errors

Author: BobobUnicorn

src/cdk/tree/nested-node.ts

@@ -95,7 +95,7 @@ export class CdkNestedTreeNode<T, K = T>
     }
     if (outlet && this._children) {
       const viewContainer = outlet.viewContainer;
-      this._tree._renderNodeChanges(this._children, this._dataDiffer, viewContainer, this._data);
+      this._tree.renderNodeChanges(this._children, this._dataDiffer, viewContainer, this._data);
     } else {
       // Reset the data differ if there's no children nodes displayed
       this._dataDiffer.diff([]);

src/cdk/tree/tree.ts

@@ -706,25 +706,9 @@ export class CdkTree<T, K = T> implements AfterContentChecked, CollectionViewer,
     return group.indexOf(dataNode) + 1;
   }
 
-  /**
-   * Adds the specified node component to the tree's internal registry.
-   *
-   * This primarily facilitates keyboard navigation.
-   */
-  _registerNode(node: CdkTreeNode<T, K>) {
-    this._nodes.value.set(this._trackExpansionKey(node.data), node);
-    this._nodes.next(this._nodes.value);
-  }
-
-  /** Removes the specified node component from the tree's internal registry. */
-  _unregisterNode(node: CdkTreeNode<T, K>) {
-    this._nodes.value.delete(this._trackExpansionKey(node.data));
-    this._nodes.next(this._nodes.value);
-  }
-
   /** Given a CdkTreeNode, gets the node that renders that node's parent's data. */
   _getNodeParent(node: CdkTreeNode<T, K>) {
-    const parent = this._parents.get(node.data);
+    const parent = this._parents.get(this._getExpansionKey(node.data));
     return parent && this._nodes.value.get(this._getExpansionKey(parent));
   }
 
@@ -832,22 +816,6 @@ export class CdkTree<T, K = T> implements AfterContentChecked, CollectionViewer,
     return this.expansionKey?.(dataNode) ?? (dataNode as unknown as K);
   }
 
-  private _flattenChildren(nodes: readonly T[]): Observable<readonly T[]> {
-    // If we're using TreeControl or levelAccessor, we don't need to manually
-    // flatten things here.
-    if (!this.childrenAccessor) {
-      return observableOf(nodes);
-    } else {
-      return observableOf(...nodes).pipe(
-        concatMap(node => concat(observableOf([node]), this._getAllChildrenRecursively(node))),
-        reduce((results, nodes) => {
-          results.push(...nodes);
-          return results;
-        }, [] as T[]),
-      );
-    }
-  }
-
   private _getNodeGroup(node: T) {
     const level = this._levels.get(this._getExpansionKey(node));
     const parent = this._parents.get(this._getExpansionKey(node));