Bug 11748 switch to new DecoratorManager API
From the workbench change notes: API changes IWorkbenchPartSite.getDecoratorManager() - As the DecoratorManager has proven to be required for more than just IWorkbenchPartSites we have moved getDecoratorManager() to IWorkbench and deprecated the getDecoratorManager() in IWorkbenchPartSite. The one in IWorkbenchPartSite will be removed after the other Eclipse components have had a chance to switch to the new API.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
else if (obj instanceof IFile)
				element= obj;
				
			if (element == null)
				return;
			IWorkbenchPage page= getSite().getPage();
			IEditorPart editorArray[]= page.getEditors();
			for (int i= 0; i < editorArray.length; ++i) {
				IEditorPart editor= editorArray[i];
				Object input= getElementOfInput(editor.getEditorInput());					
				if (input != null && input.equals(element)) {
					page.bringToTop(editor);
					if (obj instanceof IJavaElement) 
						EditorUtility.revealInEditor(editor, (IJavaElement) obj);
					return;
				}
			}
		}
	}
	private IResource getResourceFor(Object element) {
		if (element instanceof IJavaElement) {
			if (element instanceof IWorkingCopy) {
				IWorkingCopy wc= (IWorkingCopy)element;
				IJavaElement original= wc.getOriginalElement();
				if (original != null)
					element= original;
			}
			try {
				element= ((IJavaElement)element).getUnderlyingResource();
			} catch (JavaModelException e) {