3 files changed, 194 insertions, 0 deletions
diff --git a/components/script/dom/mod.rs b/components/script/dom/mod.rs
index fba7200c892..47b9bed795f 100644
--- a/components/script/dom/mod.rs
+++ b/components/script/dom/mod.rs
@@ -538,6 +538,7 @@ pub mod vrfieldofview;
 pub mod vrframedata;
 pub mod vrpose;
 pub mod vrstageparameters;
+pub mod vttregion;
 pub mod webgl_extensions;
 pub use self::webgl_extensions::ext::*;
 pub mod webgl2renderingcontext;
diff --git a/components/script/dom/vttregion.rs b/components/script/dom/vttregion.rs
new file mode 100644
index 00000000000..167e9fa37bf
--- /dev/null
+++ b/components/script/dom/vttregion.rs
@@ -0,0 +1,167 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+use crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::VTTRegionBinding::{
+    self, ScrollSetting, VTTRegionMethods,
+};
+use crate::dom::bindings::error::{Error, ErrorResult, Fallible};
+use crate::dom::bindings::num::Finite;
+use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::bindings::str::DOMString;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::window::Window;
+use dom_struct::dom_struct;
+use std::cell::Cell;
+
+#[dom_struct]
+pub struct VTTRegion {
+    reflector_: Reflector,
+    id: DomRefCell<DOMString>,
+    width: Cell<f64>,
+    lines: Cell<u32>,
+    region_anchor_x: Cell<f64>,
+    region_anchor_y: Cell<f64>,
+    viewport_anchor_x: Cell<f64>,
+    viewport_anchor_y: Cell<f64>,
+    scroll: Cell<ScrollSetting>,
+}
+
+impl VTTRegion {
+    pub fn new_inherited() -> Self {
+        VTTRegion {
+            reflector_: Reflector::new(),
+            id: DomRefCell::new(DOMString::default()),
+            width: Cell::new(100_f64),
+            lines: Cell::new(3),
+            region_anchor_x: Cell::new(0_f64),
+            region_anchor_y: Cell::new(100_f64),
+            viewport_anchor_x: Cell::new(0_f64),
+            viewport_anchor_y: Cell::new(100_f64),
+            scroll: Cell::new(Default::default()),
+        }
+    }
+
+    pub fn new(global: &GlobalScope) -> DomRoot<Self> {
+        reflect_dom_object(
+            Box::new(Self::new_inherited()),
+            global,
+            VTTRegionBinding::Wrap,
+        )
+    }
+
+    #[allow(non_snake_case)]
+    pub fn Constructor(window: &Window) -> Fallible<DomRoot<Self>> {
+        Ok(VTTRegion::new(&window.global()))
+    }
+}
+
+impl VTTRegionMethods for VTTRegion {
+    // https://w3c.github.io/webvtt/#dom-vttregion-id
+    fn Id(&self) -> DOMString {
+        self.id.borrow().clone()
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-id
+    fn SetId(&self, value: DOMString) {
+        *self.id.borrow_mut() = value;
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-width
+    fn Width(&self) -> Finite<f64> {
+        Finite::wrap(self.width.get())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-width
+    fn SetWidth(&self, value: Finite<f64>) -> ErrorResult {
+        if *value < 0_f64 || *value > 100_f64 {
+            return Err(Error::IndexSize);
+        }
+
+        self.width.set(*value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-lines
+    fn Lines(&self) -> u32 {
+        self.lines.get()
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-lines
+    fn SetLines(&self, value: u32) -> ErrorResult {
+        self.lines.set(value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-regionanchorx
+    fn RegionAnchorX(&self) -> Finite<f64> {
+        Finite::wrap(self.region_anchor_x.get())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-regionanchorx
+    fn SetRegionAnchorX(&self, value: Finite<f64>) -> ErrorResult {
+        if *value < 0_f64 || *value > 100_f64 {
+            return Err(Error::IndexSize);
+        }
+
+        self.region_anchor_x.set(*value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-regionanchory
+    fn RegionAnchorY(&self) -> Finite<f64> {
+        Finite::wrap(self.region_anchor_y.get())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-regionanchory
+    fn SetRegionAnchorY(&self, value: Finite<f64>) -> ErrorResult {
+        if *value < 0_f64 || *value > 100_f64 {
+            return Err(Error::IndexSize);
+        }
+
+        self.region_anchor_y.set(*value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-viewportanchorx
+    fn ViewportAnchorX(&self) -> Finite<f64> {
+        Finite::wrap(self.viewport_anchor_x.get())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-viewportanchorx
+    fn SetViewportAnchorX(&self, value: Finite<f64>) -> ErrorResult {
+        if *value < 0_f64 || *value > 100_f64 {
+            return Err(Error::IndexSize);
+        }
+
+        self.viewport_anchor_x.set(*value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-viewportanchory
+    fn ViewportAnchorY(&self) -> Finite<f64> {
+        Finite::wrap(self.viewport_anchor_y.get())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-viewportanchory
+    fn SetViewportAnchorY(&self, value: Finite<f64>) -> ErrorResult {
+        if *value < 0_f64 || *value > 100_f64 {
+            return Err(Error::IndexSize);
+        }
+
+        self.viewport_anchor_y.set(*value);
+        Ok(())
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-scroll
+    fn Scroll(&self) -> ScrollSetting {
+        self.scroll.get()
+    }
+
+    // https://w3c.github.io/webvtt/#dom-vttregion-scroll
+    fn SetScroll(&self, value: ScrollSetting) {
+        self.scroll.set(value);
+    }
+}
diff --git a/components/script/dom/webidls/VTTRegion.webidl b/components/script/dom/webidls/VTTRegion.webidl
new file mode 100644
index 00000000000..12fbe16170b
--- /dev/null
+++ b/components/script/dom/webidls/VTTRegion.webidl
@@ -0,0 +1,26 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+// https://w3c.github.io/webvtt/#the-vttregion-interface
+
+enum ScrollSetting { "" /* none */, "up"};
+
+[Pref="dom.webvtt.enabled", Exposed=Window]
+interface VTTRegion {
+  [Throws] constructor();
+  attribute DOMString id;
+  [SetterThrows]
+  attribute double width;
+  [SetterThrows]
+  attribute unsigned long lines;
+  [SetterThrows]
+  attribute double regionAnchorX;
+  [SetterThrows]
+  attribute double regionAnchorY;
+  [SetterThrows]
+  attribute double viewportAnchorX;
+  [SetterThrows]
+  attribute double viewportAnchorY;
+  attribute ScrollSetting scroll;
+};