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/browsing/JavaBrowsingPart.java
else if (input instanceof Collection) {
			if (((Collection)input).isEmpty())
				setTitleImage(fOriginalTitleImage);
			else {
				Object firstElement= ((Collection)input).iterator().next();
				setTitleImage(fTitleProvider.getImage(firstElement));
			}
		} else
			setTitleImage(fTitleProvider.getImage(input));
		setViewerInput(input);
	}
	private void setViewerInput(Object input) {
		fProcessSelectionEvents= false;
		fViewer.setInput(input);
		fProcessSelectionEvents= true;
	}
	/**
	 * Sets or clears the title image of this part and
	 * store the orignal image on the first call.
	 */
	protected void setTitleImage(Image titleImage) {
		if (fOriginalTitleImage == null)
			fOriginalTitleImage= getTitleImage();
		if (titleImage == null)
			titleImage= fOriginalTitleImage;
		super.setTitleImage(titleImage);
	}
	protected final StructuredViewer getViewer() {
		return fViewer;
	}