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/AbstractTableViewer.java
* (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.StructuredViewer#assertContentProviderType(org.eclipse.jface.viewers.IContentProvider)
	 */
	protected void assertContentProviderType(IContentProvider provider) {
		Assert.isTrue(provider instanceof IStructuredContentProvider
				|| provider instanceof ILazyContentProvider);
	}
	/**
	 * Searches the receiver's list starting at the first item (index 0) until
	 * an item is found that is equal to the argument, and returns the index of
	 * that item. If no item is found, returns -1.
	 * 
	 * @param item
	 *            the search item
	 * @return the index of the item
	 * 
	 * @since 3.3
	 */
	protected abstract int doIndexOf(Item item);
	/**
	 * Returns the number of items contained in the receiver.
	 * 
	 * @return the number of items
	 * 
	 * @since 3.3
	 */
	protected abstract int doGetItemCount();
	/**
	 * Sets the number of items contained in the receiver.