Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
fMouseListener= null;
		}
	}
	
	/**
	 * Returns a segmentation of the line of the given viewer's input document appropriate for
	 * bidi rendering. The default implementation returns only the string literals of a java code
	 * line as segments.
	 * 
	 * @param viewer the text viewer
	 * @param lineOffset the offset of the line
	 * @return the line's bidi segmentation
	 * @throws BadLocationException in case lineOffset is not valid in document
	 */
	public static int[] getBidiLineSegments(ITextViewer viewer, int lineOffset) throws BadLocationException {
			
		IDocument document= viewer.getDocument();
		if (document == null)
			return null;
			
		IRegion line= document.getLineInformationOfOffset(lineOffset);
		ITypedRegion[] linePartitioning= TextUtilities.computePartitioning(document, IJavaPartitions.JAVA_PARTITIONING, lineOffset, line.getLength(), false);
		
		List segmentation= new ArrayList();
		for (int i= 0; i < linePartitioning.length; i++) {
			if (IJavaPartitions.JAVA_STRING.equals(linePartitioning[i].getType()))
				segmentation.add(linePartitioning[i]);
		}