script: Move webaudio DOM interfaces to script/dom/audio/ (#38894)

Moves interfaces defined by the webaudio spec (27 files) to the new
`script/dom/audio/` module from the `script/dom/` module.

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

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

components/script/dom/audio/gainnode.rs

@@ -0,0 +1,121 @@
+/* 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 std::f32;
+
+use dom_struct::dom_struct;
+use js::rust::HandleObject;
+use servo_media::audio::gain_node::GainNodeOptions;
+use servo_media::audio::node::{AudioNodeInit, AudioNodeType};
+use servo_media::audio::param::ParamType;
+
+use crate::conversions::Convert;
+use crate::dom::audio::audionode::{AudioNode, AudioNodeOptionsHelper};
+use crate::dom::audio::audioparam::AudioParam;
+use crate::dom::audio::baseaudiocontext::BaseAudioContext;
+use crate::dom::bindings::codegen::Bindings::AudioNodeBinding::{
+    ChannelCountMode, ChannelInterpretation,
+};
+use crate::dom::bindings::codegen::Bindings::AudioParamBinding::AutomationRate;
+use crate::dom::bindings::codegen::Bindings::GainNodeBinding::{GainNodeMethods, GainOptions};
+use crate::dom::bindings::error::Fallible;
+use crate::dom::bindings::reflector::reflect_dom_object_with_proto;
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::window::Window;
+use crate::script_runtime::CanGc;
+
+#[dom_struct]
+pub(crate) struct GainNode {
+    node: AudioNode,
+    gain: Dom<AudioParam>,
+}
+
+impl GainNode {
+    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
+    pub(crate) fn new_inherited(
+        window: &Window,
+        context: &BaseAudioContext,
+        options: &GainOptions,
+        can_gc: CanGc,
+    ) -> Fallible<GainNode> {
+        let node_options =
+            options
+                .parent
+                .unwrap_or(2, ChannelCountMode::Max, ChannelInterpretation::Speakers);
+        let gain = *options.gain;
+        let node = AudioNode::new_inherited(
+            AudioNodeInit::GainNode(options.convert()),
+            context,
+            node_options,
+            1, // inputs
+            1, // outputs
+        )?;
+        let gain = AudioParam::new(
+            window,
+            context,
+            node.node_id(),
+            AudioNodeType::GainNode,
+            ParamType::Gain,
+            AutomationRate::A_rate,
+            gain,     // default value
+            f32::MIN, // min value
+            f32::MAX, // max value
+            can_gc,
+        );
+        Ok(GainNode {
+            node,
+            gain: Dom::from_ref(&gain),
+        })
+    }
+
+    pub(crate) fn new(
+        window: &Window,
+        context: &BaseAudioContext,
+        options: &GainOptions,
+        can_gc: CanGc,
+    ) -> Fallible<DomRoot<GainNode>> {
+        Self::new_with_proto(window, None, context, options, can_gc)
+    }
+
+    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
+    fn new_with_proto(
+        window: &Window,
+        proto: Option<HandleObject>,
+        context: &BaseAudioContext,
+        options: &GainOptions,
+        can_gc: CanGc,
+    ) -> Fallible<DomRoot<GainNode>> {
+        let node = GainNode::new_inherited(window, context, options, can_gc)?;
+        Ok(reflect_dom_object_with_proto(
+            Box::new(node),
+            window,
+            proto,
+            can_gc,
+        ))
+    }
+}
+
+impl GainNodeMethods<crate::DomTypeHolder> for GainNode {
+    // https://webaudio.github.io/web-audio-api/#dom-gainnode-gainnode
+    fn Constructor(
+        window: &Window,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+        context: &BaseAudioContext,
+        options: &GainOptions,
+    ) -> Fallible<DomRoot<GainNode>> {
+        GainNode::new_with_proto(window, proto, context, options, can_gc)
+    }
+
+    // https://webaudio.github.io/web-audio-api/#dom-gainnode-gain
+    fn Gain(&self) -> DomRoot<AudioParam> {
+        DomRoot::from_ref(&self.gain)
+    }
+}
+
+impl Convert<GainNodeOptions> for GainOptions {
+    fn convert(self) -> GainNodeOptions {
+        GainNodeOptions { gain: *self.gain }
+    }
+}