Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentExtension.java
}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.navigator.INavigatorContentExtension#getContentProvider()
	 */
	public ITreeContentProvider getContentProvider() {
		ITreeContentProvider provider = internalGetContentProvider();
		if (provider != SkeletonTreeContentProvider.INSTANCE)
			return ((SafeDelegateTreeContentProvider) provider)
					.getDelegateContentProvider();
		return provider;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtension#getContentProvider()
	 */
	public ITreeContentProvider internalGetContentProvider() {
		if (contentProvider != null || contentProviderInitializationFailed)
			return contentProvider;
		synchronized (this) {
			try {
				if (contentProvider == null) {
					ITreeContentProvider treeContentProvider = descriptor
							.createContentProvider();
					if (treeContentProvider != null) {
						contentProvider = new SafeDelegateTreeContentProvider(
								treeContentProvider, descriptor, contentService);
						contentProvider.init(new CommonContentExtensionSite(