Corrected method name TreeDataProvider#getTreeData (#11286)
* Corrected method name TreeDataProvider#getTreeData
The method name was incorrect in the documentation - was showing `getData()` but should be `getTreeData()`.
Refactor common methods in in-memory data providers (#9308)
* Refactor common methods of InMemoryHierarchicalDataProvider and ListDataProvider to a single interface
* Rename HierarchyData and InMemoryHierarchicalDataProvider, introduce HasHierarchicalDataProvider
* Additionally adds a helper method for recursive constructing
TreeData with a child item provider.
Add server-side expand and collapse to TreeGrid (#9021)
* Add server-side expand and collapse to TreeGrid
* Add javadocs
* Fix variable naming in TreeGridHugeTreeTest
* Fix review comments
* Merge remote-tracking branch 'github/master' into 8759-server-expand
* Clear pending expands when all data is dropped
* Add documentation