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/TreeViewer.java
/**
	 * TreeColorAndFontCollector is an helper class for color and font support
	 * for trees that support the ITableFontProvider and the
	 * ITableColorProvider.
	 * 
	 * @see ITableColorProvider
	 * @see ITableFontProvider
	 */
	private class TreeColorAndFontCollector {
		ITableFontProvider fontProvider = null;
		ITableColorProvider colorProvider = null;
		/**
		 * Create an instance of the receiver. Set the color and font providers
		 * if provider can be cast to the correct type.
		 * 
		 * @param provider
		 *            IBaseLabelProvider
		 */
		public TreeColorAndFontCollector(IBaseLabelProvider provider) {
			if (provider instanceof ITableFontProvider)
				fontProvider = (ITableFontProvider) provider;
			if (provider instanceof ITableColorProvider)
				colorProvider = (ITableColorProvider) provider;
		}
		/**
		 * Create an instance of the receiver with no color and font providers.