Refactor background directories

src/background/shared/completions/tabs.js

@@ -0,0 +1,10 @@
+const getCompletions = (keyword) => {
+  return browser.tabs.query({ currentWindow: true }).then((tabs) => {
+    let matched = tabs.filter((t) => {
+      return t.url.includes(keyword) || t.title && t.title.includes(keyword);
+    });
+    return matched;
+  });
+};
+
+export { getCompletions };