Bug 213166 [Viewers] Problems with OwnerDrawLabelProvider.setUpOwnerDraw
3.4 M4 To set up the owner draw callbacks for a viewer OwnerDrawLabelProvider.setUpOwnerDraw is offered. The problem of this is: a. there's no way to uninstall the callbacks. In our views we want to allow to enable and disable owner draw in the preferences b. from an API client perspective, it would be nicer if the label provider could install itself when installed. A good solution would be to add more life cycle to a label provider. CellLabelProvider.initialize(ColumnViewer, int column) There's already ILableProvider.dispose when a label provider is removed from a viewer.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/SimpleStyledCellLabelProvider.java
*/
	private TextLayout getTextLayoutForInfo(Display display,
			LabelPresentationInfo labelPresentation, boolean applyColors) {
		
		if (cachedLabelInfo == labelPresentation
				&& applyColors == cachedWasWithColors) {
			return cachedTextLayout; 
		}
		TextLayout sharedLayout = getSharedTextLayout(display);
		applyInfoToLayout(sharedLayout, labelPresentation, applyColors);
		cachedLabelInfo = labelPresentation;
		cachedWasWithColors = applyColors;
		return sharedLayout;
	}
	/**
	 * Fills the given text layout with the styles, text and font of the label
	 * info.
	 * 
	 * @param layout
	 *            the text layout to fill
	 * @param labelInfo
	 *            the viewer label
	 * @param applyColors
	 *            is set, colors will be used
	 */
	private void applyInfoToLayout(TextLayout layout,
			LabelPresentationInfo labelInfo, boolean applyColors) {
		layout.setText(""); 
		layout.setText(labelInfo.getText());
		layout.setFont(labelInfo.getDefaultFont());