Adding explicit returns for remaining instances

src/vs/workbench/api/node/extHostDocuments.ts

@@ -78,12 +78,13 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 
 	public getDocumentData(resource: vscode.Uri): ExtHostDocumentData {
 		if (!resource) {
-			return;
+			return undefined;
 		}
 		const data = this._documentData.get(resource.toString());
 		if (data) {
 			return data;
 		}
+		return undefined;
 	}
 
 	public ensureDocumentData(uri: URI): TPromise<ExtHostDocumentData> {