web: On browsers which support it, specify the type of audio Ruffle uses

web/packages/core/src/plugin-polyfill.ts

@@ -231,6 +231,9 @@ declare global {
     interface MimeTypeArray {
         install?: (mimeType: MimeType) => void;
     }
+    interface AudioSession {
+        type?: string;
+    }
 }
 
 /**
@@ -244,6 +247,11 @@ declare global {
  * @param plugin The plugin to install
  */
 export function installPlugin(plugin: RufflePlugin): void {
+    // This code is not polyfill related, but while messing with the navigator API,
+    // we can specify https://www.w3.org/TR/audio-session/#audio-session-types
+    if ("audioSession" in navigator) {
+        (navigator.audioSession as AudioSession).type = "playback";
+    }
     if (navigator.plugins.namedItem("Shockwave Flash")) {
         return;
     }