src/vs/editor/common/viewModel/viewModelImpl.ts/ViewModel/reduceRestoreState
class ViewModel:	public reduceRestoreState(state: IViewState): { scrollLeft: number; scrollTop: number } {
		if (typeof state.firstPosition === 'undefined') {
			// This is a view state serialized by an older version
			return this._reduceRestoreStateCompatibility(state);
		}

		const modelPosition = this.model.validatePosition(state.firstPosition);
		const viewPosition = this.coordinatesConverter.convertModelPositionToViewPosition(modelPosition);
		const scrollTop = this.viewLayout.getVerticalOffsetForLineNumber(viewPosition.lineNumber) - state.firstPositionDeltaTop;
		return {
			scrollLeft: state.scrollLeft,
			scrollTop: scrollTop
		};
	}