src/vs/base/browser/ui/scrollbar/scrollbarState.ts/ScrollbarState/setVisibleSize
class ScrollbarState:	public setVisibleSize(visibleSize: number): boolean {
		const iVisibleSize = Math.round(visibleSize);
		if (this._visibleSize !== iVisibleSize) {
			this._visibleSize = iVisibleSize;
			this._refreshComputedValues();
			return true;
		}
		return false;
	}