moebius#339: Make it possible to add cookies, local and session storage entries

Issue #31
https://github.com/MoonchildProductions/moebius/pull/339

devtools/client/storage/test/head.js

@@ -897,3 +897,39 @@ function setPermission(url, permission) {
             .addFromPrincipal(principal, permission,
                               nsIPermissionManager.ALLOW_ACTION);
 }
+
+/**
+ * Add an item.
+ * @param  {Array} store
+ *         An array containing the path to the store to which we wish to add an
+ *         item.
+ */
+function* performAdd(store) {
+  let storeName = store.join(" > ");
+  let toolbar = gPanelWindow.document.getElementById("storage-toolbar");
+  let type = store[0];
+
+  yield selectTreeItem(store);
+
+  let menuAdd = toolbar.querySelector(
+    "#add-button");
+
+  if (menuAdd.hidden) {
+    is(menuAdd.hidden, false,
+       `performAdd called for ${storeName} but it is not supported`);
+    return;
+  }
+
+  let eventEdit = gUI.table.once("row-edit");
+  let eventWait = gUI.once("store-objects-updated");
+
+  menuAdd.click();
+
+  let rowId = yield eventEdit;
+  yield eventWait;
+
+  let key = type === "cookies" ? "uniqueKey" : "name";
+  let value = getCellValue(rowId, key);
+
+  is(rowId, value, `Row '${rowId}' was successfully added.`);
+}