Bug 174701 [Viewers] ViewerRow should be reused instead of connected to the Item
Currently we create a ViewerRow ver every Item we create this can degrade performance, we should cache the row and reuse it
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewerFocusCellManager.java
private static final CellNavigationStrategy TREE_NAVIGATE = new CellNavigationStrategy() {
		public void collapse(ColumnViewer viewer, ViewerCell cellToCollapse,
				Event event) {
			if (cellToCollapse != null) {
				((TreeItem) cellToCollapse.getItem()).setExpanded(false);
			}
		}
		public void expand(ColumnViewer viewer, ViewerCell cellToExpand,
				Event event) {
			if (cellToExpand != null) {
				TreeViewer v = (TreeViewer) viewer;
				v.setExpandedState(v
						.getTreePathFromItem(cellToExpand.getItem()), true);
			}
		}
		public boolean isCollapseEvent(ColumnViewer viewer,
				ViewerCell cellToCollapse, Event event) {
			return cellToCollapse != null
					&& ((TreeItem) cellToCollapse.getItem()).getExpanded()
					&& cellToCollapse.getColumnIndex() == 0
					&& event.keyCode == SWT.ARROW_LEFT;