Bug 65378 FindOccurencesCUEngine should use ASTProvider
RC1 FindOccurrencesEngine should get the AST from the ASTProvider so it can profit if the AST is already cached (2 occurences) e.g. JaavPlugin.getDefault().getASTProvider().getAST(cu)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/search/FindOccurrencesEngine.java
private ICompilationUnit fCUnit;
		
		public FindOccurencesCUEngine(ICompilationUnit unit, IOccurrencesFinder finder) {
			super(finder);
			fCUnit= unit;
		}
		protected CompilationUnit createAST() {
			ASTParser p= ASTParser.newParser(AST.JLS2);
			p.setSource(fCUnit);
			p.setResolveBindings(true);
			return (CompilationUnit) p.createAST(null);
		}
		protected IJavaElement getInput() {
			return fCUnit;
		}
		protected IResource getMarkerOwner() throws JavaModelException {
			ICompilationUnit original= WorkingCopyUtil.getOriginal(fCUnit);
			return original.getUnderlyingResource();
		}
		protected void addSpecialAttributes(Map attributes) {
			
		}
		protected ISourceReference getSourceReference() {
			return fCUnit;
		}