Bug 89971 [Viewers] Viewers that use IViewerLabelProvider do too many instanceof checks
M6 Checking our viewer the calls to buildLabel are doing too many instanceof checks. As a result certain viewers (such as the table viewer) are twice as slow as they were in 3.0 due to these checks. I have written some performance suites to test the Table, Tree, List and Combo viewers. Table and Tree have this issue.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
}
	}
	/**
	 * Discards this viewer's filters and triggers refiltering and resorting of
	 * the elements.
	 */
	public void resetFilters() {
		if (filters != null) {
			filters = null;
			refresh();
		}
	}
	/**
	 * Ensures that the given element is visible, scrolling the viewer if
	 * necessary. The selection is unchanged.
	 * 
	 * @param element
	 *            the element to reveal
	 */
	public abstract void reveal(Object element);
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ContentViewer#setContentProvider(org.eclipse.jface.viewers.IContentProvider)
	 */
	public void setContentProvider(IContentProvider provider) {
		assertContentProviderType(provider);
		super.setContentProvider(provider);
	}
	/**
	 * Assert that the content provider is of one of the