Merge from vscode 3a6dcb42008d509900b3a3b2d695564eeb4dbdac (#5098)

src/vs/vscode.proposed.d.ts

@@ -1371,4 +1371,43 @@ declare module 'vscode' {
 		group?: string;
 	}
 	//#endregion
+
+	//#region Workspace URI Ben
+
+	export namespace workspace {
+
+		/**
+		 * The location of the workspace file, for example:
+		 *
+		 * `file:///Users/name/Development/myProject.code-workspace`
+		 *
+		 * or
+		 *
+		 * `untitled:1555503116870`
+		 *
+		 * for a workspace that is untitled and not yet saved.
+		 *
+		 * Depending on the workspace that is opened, the value will be:
+		 *  * `undefined` when no workspace or  a single folder is opened
+		 *  * the path of the workspace file as `Uri` otherwise. if the workspace
+		 * is untitled, the returned URI will use the `untitled:` scheme
+		 *
+		 * The location can e.g. be used with the `vscode.openFolder` command to
+		 * open the workspace again after it has been closed.
+		 *
+		 * **Example:**
+		 * ```typescript
+		 * vscode.commands.executeCommand('vscode.openFolder', uriOfWorkspace);
+		 * ```
+		 *
+		 * **Note:** it is not advised to use `workspace.workspaceFile` to write
+		 * configuration data into the file. You can use `workspace.getConfiguration().update()`
+		 * for that purpose which will work both when a single folder is opened as
+		 * well as an untitled or saved workspace.
+		 */
+		export const workspaceFile: Uri | undefined;
+	}
+
+	//#endregion
+
 }