src/vs/editor/browser/services/abstractCodeEditorService.ts/DecorationCSSRules/dispose
class DecorationCSSRules:	public dispose() {
		if (this._hasContent) {
			this._removeCSS();
			this._hasContent = false;
		}
		if (this._themeListener) {
			this._themeListener.dispose();
			this._themeListener = null;
		}
	}