src/vs/workbench/services/textMate/electron-sandbox/textMateService.ts/TextMateService/_onModelRemoved
class TextMateService:	private _onModelRemoved(model: ITextModel): void {
		const key = model.uri.toString();
		if (this._tokenizers[key]) {
			this._tokenizers[key].dispose();
			delete this._tokenizers[key];
		}
	}