src/vs/base/browser/ui/scrollbar/scrollbarVisibilityController.ts/ScrollbarVisibilityController/setIsNeeded
class ScrollbarVisibilityController:	public setIsNeeded(isNeeded: boolean): void {
		if (this._isNeeded !== isNeeded) {
			this._isNeeded = isNeeded;
			this.ensureVisibility();
		}
	}