LibWeb: Start filling out BaseAudioContext/AudioContext interfaces

- Fills out both IDLs and implements some basic attributes/methods.
- No actual audio processing yet though :^)

Userland/Libraries/LibWeb/WebAudio/AudioContext.idl

@@ -1,8 +1,31 @@
 #import <WebAudio/BaseAudioContext.idl>
 
+// https://www.w3.org/TR/webaudio/#enumdef-audiocontextlatencycategory
+enum AudioContextLatencyCategory { "balanced", "interactive", "playback" };
+
 // https://webaudio.github.io/web-audio-api/#AudioContext
 [Exposed=Window]
 interface AudioContext : BaseAudioContext {
-    // FIXME: Should be constructor (optional AudioContextOptions contextOptions = {});
-    constructor();
+    constructor(optional AudioContextOptions contextOptions = {});
+    readonly attribute double baseLatency;
+    readonly attribute double outputLatency;
+    AudioTimestamp getOutputTimestamp ();
+    Promise<undefined> resume ();
+    Promise<undefined> suspend ();
+    Promise<undefined> close ();
+    // FIXME: MediaElementAudioSourceNode createMediaElementSource (HTMLMediaElement mediaElement);
+    // FIXME: MediaStreamAudioSourceNode createMediaStreamSource (MediaStream mediaStream);
+    // FIXME: MediaStreamTrackAudioSourceNode createMediaStreamTrackSource (MediaStreamTrack mediaStreamTrack);
+    // FIXME: MediaStreamAudioDestinationNode createMediaStreamDestination ();
+};
+
+dictionary AudioContextOptions {
+  AudioContextLatencyCategory latencyHint = "interactive";
+  float sampleRate;
+};
+
+dictionary AudioTimestamp {
+  double contextTime;
+  // FIXME: Should be DOMHighResTimeStamp, but DOMHighResTimeStamp doesn't get parsed as a double during codegen
+  double performanceTime;
 };