Bug 167323 [Viewers]Open AbstractTreeViewer for external widget implementors
As reported by Ross Camara AbstractTreeViewer would work for nebula if we would open the API a bit. Boris and I decided that we will do this in 2 steps: 1. open the API 2. moving the Virtual-Support bits from TreeViewer to AbstractTreeViewer when the nebula grid provides virtual support.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTableViewer.java
Object element = virtualManager.cachedElements[i];
					if (virtualElements.contains(element)) {
						Item item = doGetItem(i);
						item.getText();
						indices[count++] = i;
						virtualElements.remove(element);
						if (firstItem == null) {
							firstItem = item;
						}
					}
				}
			}
		}
		if (count < size) {
			System.arraycopy(indices, 0, indices = new int[count], 0, count);
		}
		doSetSelection(indices);
		if (reveal && firstItem != null) {
			doShowItem(firstItem);
		}
	}
	/**
	 * Set the item count of the receiver.
	 * 
	 * @param count
	 *            the new table size.
	 * 
	 * @since 3.1
	 */
	public void setItemCount(int count) {