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 (input instanceof IFileEditorInput)
			return ((IFileEditorInput)input).getFile();
		else if (input instanceof JarEntryEditorInput)
			return ((JarEntryEditorInput)input).getStorage();
		return null;
	}
	
	/**
 	 * Returns the Viewer.
 	 */
	TreeViewer getViewer() {
		return fViewer;
	}
	
	/**
 	 * Returns the pattern filter for this view.
 	 * @return the pattern filter
 	 */
	JavaElementPatternFilter getPatternFilter() {
		return fPatternFilter;
	}
	
	/**
 	 * Returns the library filter for this view.
 	 * @return the library filter
 	 */
	LibraryFilter getLibraryFilter() {
		return fLibraryFilter;
	}
	/**