[Web] Fix audio issues with samples and GodotPositionReportingProcessor

[adamscott]

This PR pools the GodotPositionReportingProcessor worklets created instead of creating new worklets every time. This seems to prevent an escalation in memory usage over time.

Fixes #98731.

[rburing]

Fixes the issue in my project, cf. #98731 (comment). Thanks!

[Repiteo]

Thanks!

[mooflu]

According to the spec https://developer.mozilla.org/en-US/docs/Web/API/AudioWorkletProcessor/process - returning true will force the AudioWorkletNode to remain active. I.e. I think this will keep processing even after it's been disconnected. Instead of adding a pool wouldn't it be easier to just return false here when it's disconnected?

i.e. something like this:

this._positionWorklet.port.postMessage('stop'); // tell the processor to stop
this._positionWorklet.disconnect();

class GodotPositionReportingProcessor extends AudioWorkletProcessor {
	constructor() {
		super();
		this.position = 0;
		this.running = true;
		this.port.onmessage = (event) => {
			if (event.data === 'stop') {
				this.running = false;
			}
		};
	}

	process(inputs, _outputs, _parameters) {
		if (inputs.length > 0) {
			const input = inputs[0];
			if (input.length > 0) {
				this.position += input[0].length;
				this.port.postMessage({ 'type': 'position', 'data': this.position });
				return true;
			}
		}
		if (!this.running) {
			this.port.onmessage = null;
		}
		return this.running;
	}
}

[adamscott]

I'll test it out! Thanks!