script: Move gamepad DOM interfaces to script/dom/gamepad/ (#38900)

Moves interfaces defined by the gamepad spec to the
`script/dom/gamepad/` module from `script/dom/`.

Testing: Just a refactor shouldn't need any testing
Fixes: N/A

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>

components/script/dom/gamepad/gamepadbuttonlist.rs

@@ -0,0 +1,88 @@
+/* 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 dom_struct::dom_struct;
+
+use crate::dom::bindings::codegen::Bindings::GamepadButtonListBinding::GamepadButtonListMethods;
+use crate::dom::bindings::reflector::{Reflector, reflect_dom_object};
+use crate::dom::bindings::root::{Dom, DomRoot, DomSlice};
+use crate::dom::gamepad::gamepadbutton::GamepadButton;
+use crate::dom::window::Window;
+use crate::script_runtime::CanGc;
+
+// https://w3c.github.io/gamepad/#gamepadbutton-interface
+#[dom_struct]
+pub(crate) struct GamepadButtonList {
+    reflector_: Reflector,
+    list: Vec<Dom<GamepadButton>>,
+}
+
+impl GamepadButtonList {
+    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
+    fn new_inherited(list: &[&GamepadButton]) -> GamepadButtonList {
+        GamepadButtonList {
+            reflector_: Reflector::new(),
+            list: list.iter().map(|button| Dom::from_ref(*button)).collect(),
+        }
+    }
+
+    pub(crate) fn new(
+        window: &Window,
+        list: &[&GamepadButton],
+        can_gc: CanGc,
+    ) -> DomRoot<GamepadButtonList> {
+        reflect_dom_object(
+            Box::new(GamepadButtonList::new_inherited(list)),
+            window,
+            can_gc,
+        )
+    }
+}
+
+impl GamepadButtonListMethods<crate::DomTypeHolder> for GamepadButtonList {
+    // https://w3c.github.io/gamepad/#dom-gamepad-buttons
+    fn Length(&self) -> u32 {
+        self.list.len() as u32
+    }
+
+    // https://w3c.github.io/gamepad/#dom-gamepad-buttons
+    fn Item(&self, index: u32) -> Option<DomRoot<GamepadButton>> {
+        self.list
+            .get(index as usize)
+            .map(|button| DomRoot::from_ref(&**button))
+    }
+
+    // https://w3c.github.io/gamepad/#dom-gamepad-buttons
+    fn IndexedGetter(&self, index: u32) -> Option<DomRoot<GamepadButton>> {
+        self.Item(index)
+    }
+}
+
+impl GamepadButtonList {
+    /// Initialize the number of buttons in the "standard" gamepad mapping.
+    /// <https://www.w3.org/TR/gamepad/#dfn-initializing-buttons>
+    pub(crate) fn init_buttons(window: &Window, can_gc: CanGc) -> DomRoot<GamepadButtonList> {
+        let standard_buttons = &[
+            GamepadButton::new(window, false, false, can_gc), // Bottom button in right cluster
+            GamepadButton::new(window, false, false, can_gc), // Right button in right cluster
+            GamepadButton::new(window, false, false, can_gc), // Left button in right cluster
+            GamepadButton::new(window, false, false, can_gc), // Top button in right cluster
+            GamepadButton::new(window, false, false, can_gc), // Top left front button
+            GamepadButton::new(window, false, false, can_gc), // Top right front button
+            GamepadButton::new(window, false, false, can_gc), // Bottom left front button
+            GamepadButton::new(window, false, false, can_gc), // Bottom right front button
+            GamepadButton::new(window, false, false, can_gc), // Left button in center cluster
+            GamepadButton::new(window, false, false, can_gc), // Right button in center cluster
+            GamepadButton::new(window, false, false, can_gc), // Left stick pressed button
+            GamepadButton::new(window, false, false, can_gc), // Right stick pressed button
+            GamepadButton::new(window, false, false, can_gc), // Top button in left cluster
+            GamepadButton::new(window, false, false, can_gc), // Bottom button in left cluster
+            GamepadButton::new(window, false, false, can_gc), // Left button in left cluster
+            GamepadButton::new(window, false, false, can_gc), // Right button in left cluster
+            GamepadButton::new(window, false, false, can_gc), // Center button in center cluster
+        ];
+        rooted_vec!(let buttons <- standard_buttons.iter().map(DomRoot::as_traced));
+        Self::new(window, buttons.r(), can_gc)
+    }
+}