Add scroll logic from TreeGrid to Tree (#10005)

Fixes #9967

all/src/main/templates/release-notes.html

         <li>Row height in <tt>Grid</tt> is replaced with separate header, body and footer row heights</li>        
         <li><tt>GridState</tt> variable <tt>rowHeight</tt> has been replaced by three variables.</li>
         <li><tt>Button</tt> has a new constructor that may cause constructor calls with null as first parameter to be ambiguous.</li>
+        <li><tt>DataCommunicator</tt> method <tt>getDataProviderSize</tt> is now <tt>public</tt>, not <tt>protected</tt>.</li>
 
         <h2>For incompatible or behaviour-altering changes in 8.1, please see <a href="https://vaadin.com/download/release/8.1/8.1.0/release-notes.html#incompatible">8.1 release notes</a></h2>
         

server/src/main/java/com/vaadin/data/provider/DataCommunicator.java

      * @return the size of data provider with current filter
      */
     @SuppressWarnings({ "unchecked", "rawtypes" })
-    protected int getDataProviderSize() {
+    public int getDataProviderSize() {
         return getDataProvider().size(new Query(getFilter()));
     }
 

server/src/main/java/com/vaadin/data/provider/HierarchicalDataCommunicator.java

     }
 
     @Override
-    protected int getDataProviderSize() {
+    public int getDataProviderSize() {
         return mapper.getTreeSize();
     }
 

server/src/main/java/com/vaadin/ui/Grid.java

      * @param row
      *            zero based index of the item to scroll to in the current view.
      * @throws IllegalArgumentException
-     *             if the provided id is not recognized by the data source.
+     *            if the provided row is outside the item range
      */
     public void scrollTo(int row) throws IllegalArgumentException {
         scrollTo(row, ScrollDestination.ANY);
         Objects.requireNonNull(destination,
                 "ScrollDestination can not be null");
 
-        if (row > getDataProvider().size(new Query())) {
+        if (row > getDataCommunicator().getDataProviderSize()) {
             throw new IllegalArgumentException("Row outside dataProvider size");
         }
 

server/src/main/java/com/vaadin/ui/Tree.java

 import com.vaadin.shared.Registration;
 import com.vaadin.shared.ui.ContentMode;
 import com.vaadin.shared.ui.grid.HeightMode;
+import com.vaadin.shared.ui.grid.ScrollDestination;
 import com.vaadin.shared.ui.tree.TreeMultiSelectionModelState;
 import com.vaadin.shared.ui.tree.TreeRendererState;
 import com.vaadin.ui.Grid.SelectionMode;
             return (Tree<T>) super.getComponent();
         }
     }
+
+    /**
+     * Scrolls to a certain item, using {@link ScrollDestination#ANY}.
+     * <p>
+     * If the item has an open details row, its size will also be taken into
+     * account.
+     *
+     * @param row
+     *            zero based index of the item to scroll to in the current view.
+     * @throws IllegalArgumentException
+     *            if the provided row is outside the item range
+     */
+    public void scrollTo(int row) throws IllegalArgumentException {
+        treeGrid.scrollTo(row, ScrollDestination.ANY);
+    }
+
+    /**
+     * Scrolls to a certain item, using user-specified scroll destination.
+     * <p>
+     * If the item has an open details row, its size will also be taken into
+     * account.
+     *
+     * @param row
+     *            zero based index of the item to scroll to in the current view.
+     * @param destination
+     *            value specifying desired position of scrolled-to row, not
+     *            {@code null}
+     * @throws IllegalArgumentException
+     *             if the provided row is outside the item range
+     */
+    public void scrollTo(int row, ScrollDestination destination) {
+        treeGrid.scrollTo(row, destination);
+    }
+
+    /**
+     * Scrolls to the beginning of the first data row.
+     */
+    public void scrollToStart() {
+        treeGrid.scrollToStart();
+    }
+
+    /**
+     * Scrolls to the end of the last data row.
+     */
+    public void scrollToEnd() {
+        treeGrid.scrollToEnd();
+    }
+
 }