1 files changed, 48 insertions, 0 deletions
diff --git a/dom/webidl/ResizeObserver.webidl b/dom/webidl/ResizeObserver.webidl
new file mode 100644
index 0000000000..0a186c0a18
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+++ b/dom/webidl/ResizeObserver.webidl
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+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * https://drafts.csswg.org/resize-observer/
+ */
+
+enum ResizeObserverBoxOptions {
+    "border-box",
+    "content-box"
+};
+
+dictionary ResizeObserverOptions {
+    ResizeObserverBoxOptions box = "content-box";
+};
+
+[Exposed=Window,
+ Pref="layout.css.resizeobserver.enabled"]
+interface ResizeObserver {
+    [Throws]
+    constructor(ResizeObserverCallback callback);
+
+    [Throws]
+    void observe(Element target, optional ResizeObserverOptions options = {});
+    [Throws]
+    void unobserve(Element target);
+    void disconnect();
+};
+
+callback ResizeObserverCallback = void (sequence<ResizeObserverEntry> entries, ResizeObserver observer);
+
+[Pref="layout.css.resizeobserver.enabled",
+ Exposed=Window]
+interface ResizeObserverEntry {
+    readonly attribute Element target;
+    readonly attribute DOMRectReadOnly contentRect;
+    readonly attribute ResizeObserverSize borderBoxSize;
+    readonly attribute ResizeObserverSize contentBoxSize;
+};
+
+[Pref="layout.css.resizeobserver.enabled",
+ Exposed=Window]
+interface ResizeObserverSize {
+    readonly attribute unrestricted double inlineSize;
+    readonly attribute unrestricted double blockSize;
+};