Bug 186025 [Viewers] Virtual Manager should be cleared when Viewer is disposed
Got a nasty memory leak where the Workbench would keep my disposed viewer in a field since it was registered as a selection provider. In StructuredViewer#handleDisposed(), the input is set to null, however this does not clear a possible virtual manager being used from the Table Viewer. The Table Viewer should clear the cache of the virtual manager on handleDispose to make sure, no reference to any model object is retained.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTableViewer.java
*/
	protected abstract void doClearAll();
	/**
	 * Resets the given item in the receiver. The text, icon and other attributes
	 * of the item are set to their default values.
	 *
	 * @param item the item to reset
	 *
	 * @since 3.3
	 */
	protected abstract void doResetItem(Item item);
	/**
	 * Removes the items from the receiver which are between the given
	 * zero-relative start and end indices (inclusive).
	 *
	 * @param start
	 *            the start of the range
	 * @param end
	 *            the end of the range
	 *
	 * @exception IllegalArgumentException -
	 *                if either the start or end are not between 0 and the
	 *                number of elements in the list minus 1 (inclusive)
	 *
	 * @since 3.3
	 */
	protected abstract void doRemove(int start, int end);
	/**
	 * Removes all of the items from the receiver.
	 *