Bug 19014 Empty CU after reorg
F2 - enable single click and show in members in packages view - open TestCase.java in editor - give focus to packages view - change it on disk - copy a method in TestCase using DnD - activate the TestCase.java editor - answer question with no - activate revert from context menu observe: CU is empty
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
fSavePolicy= savePolicy;
	}
	
	/**
	 * Creates a compilation unit from the given file.
	 * 
	 * @param file the file from which to create the compilation unit
	 */
	protected ICompilationUnit createCompilationUnit(IFile file) {
		Object element= JavaCore.create(file);
		if (element instanceof ICompilationUnit)
			return (ICompilationUnit) element;
		return null;
	}
	
	/**
	 * Creates a line tracker working with the same line delimiters as the document
	 * of the given element. Assumes the element to be managed by this document provider.
	 * 
	 * @param element the element serving as blue print
	 * @return a line tracker based on the same line delimiters as the element's document
	 */
	public ILineTracker createLineTracker(Object element) {
		return new DefaultLineTracker();
	}
	/*
	 * @see AbstractDocumentProvider#createElementInfo(Object)
	 */
	protected ElementInfo createElementInfo(Object element) throws CoreException {