Bug 98107 [Viewers] Change visibility of AbstractTreeViewer#internalRemove from private to protected
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* Sets the auto-expand level. The value 0 means that there is no
     * auto-expand; 1 means that top-level elements are expanded, but not their
     * children; 2 means that top-level elements are expanded, and their
     * children, but not grandchildren; and so on.
     * <p>
     * The value <code>ALL_LEVELS</code> means that all subtrees should be
     * expanded.
     * </p>
     * 
     * @param level
     *           non-negative level, or <code>ALL_LEVELS</code> to expand all
     *           levels of the tree
     */
    public void setAutoExpandLevel(int level) {
        expandToLevel = level;
    }
    /**
     * The <code>AbstractTreeViewer</code> implementation of this method
     * checks to ensure that the content provider is an <code>ITreeContentProvider</code>.
     */
    public void setContentProvider(IContentProvider provider) {
        Assert.isTrue(provider instanceof ITreeContentProvider);
        super.setContentProvider(provider);
    }
    /**
     * Sets the expand state of the given item.
     * 
     * @param item
     *           the item
     * @param expand