1 files changed, 91 insertions, 0 deletions
diff --git a/toolkit/content/widgets/message-bar.js b/toolkit/content/widgets/message-bar.js
new file mode 100644
index 0000000000..d38347b40a
--- /dev/null
+++ b/toolkit/content/widgets/message-bar.js
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// This is loaded into chrome windows with the subscript loader. Wrap in
+// a block to prevent accidentally leaking globals onto `window`.
+{
+  class MessageBarElement extends HTMLElement {
+    constructor() {
+      super();
+      const shadowRoot = this.attachShadow({ mode: "open" });
+      window.MozXULElement?.insertFTLIfNeeded(
+        "toolkit/global/notification.ftl"
+      );
+      document.l10n.connectRoot(this.shadowRoot);
+      const content = this.constructor.template.content.cloneNode(true);
+      shadowRoot.append(content);
+      this.closeButton.addEventListener("click", () => this.dismiss(), {
+        once: true,
+      });
+    }
+
+    disconnectedCallback() {
+      this.dispatchEvent(new CustomEvent("message-bar:close"));
+    }
+
+    get closeButton() {
+      return this.shadowRoot.querySelector("button.close");
+    }
+
+    static get template() {
+      const template = document.createElement("template");
+
+      const commonStyles = document.createElement("link");
+      commonStyles.rel = "stylesheet";
+      commonStyles.href = "chrome://global/skin/in-content/common.css";
+      const messageBarStyles = document.createElement("link");
+      messageBarStyles.rel = "stylesheet";
+      messageBarStyles.href =
+        "chrome://global/content/elements/message-bar.css";
+      template.content.append(commonStyles, messageBarStyles);
+
+      // A container for the entire message bar content,
+      // most of the css rules needed to provide the
+      // expected message bar layout is applied on this
+      // element.
+      const container = document.createElement("div");
+      container.part = "container";
+      container.classList.add("container");
+      template.content.append(container);
+
+      const icon = document.createElement("span");
+      icon.classList.add("icon");
+      icon.part = "icon";
+      container.append(icon);
+
+      const barcontent = document.createElement("span");
+      barcontent.classList.add("content");
+      barcontent.append(document.createElement("slot"));
+      container.append(barcontent);
+
+      const spacer = document.createElement("span");
+      spacer.classList.add("spacer");
+      container.append(spacer);
+
+      const closeIcon = document.createElement("button");
+      closeIcon.classList.add("close", "ghost-button");
+      document.l10n.setAttributes(closeIcon, "notification-close-button");
+      container.append(closeIcon);
+
+      Object.defineProperty(this, "template", {
+        value: template,
+      });
+
+      return template;
+    }
+
+    dismiss() {
+      this.dispatchEvent(new CustomEvent("message-bar:user-dismissed"));
+      this.close();
+    }
+
+    close() {
+      this.remove();
+    }
+  }
+
+  customElements.define("message-bar", MessageBarElement);
+}