Bug 157174 [Viewers] Refactor new Viewer API
We are yet not completely happy with the API and refactor it.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerLabelProvider.java
*            <code>null</code>.
	 */
	public void setLabelProvider(ILabelProvider provider) {
		this.labelProvider = provider;
	}
	/**
	 * Set the any providers for the receiver that can be adapted from provider.
	 * 
	 * @param provider
	 *            {@link Object}
	 */
	public void setProviders(Object provider) {
		if (provider instanceof ILabelProvider)
			setLabelProvider((ILabelProvider) provider);
		if (provider instanceof IColorProvider)
			colorProvider = (IColorProvider) provider;
		if (provider instanceof IFontProvider)
			fontProvider = (IFontProvider) provider;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.IFontProvider#getFont(java.lang.Object)
	 */
	public Font getFont(Object element) {
		if (fontProvider == null) {
			return null;
		}
		return fontProvider.getFont(element);
	}