int pixel = getLinePixel(topIndex) + verticalScrollOffset; setVerticalScrollOffset(pixel, true);
int pixel = getLinePixel(topIndex); scrollVertical(pixel, true);
public void setTopIndex(int topIndex) {	checkWidget();	if (getCharCount() == 0) {		return;	}	int lineCount = content.getLineCount();	//TODO broken for variable line height	int pageSize = Math.max(1, Math.min(lineCount, getLineCountWhole()));	if (topIndex < 0) {		topIndex = 0;	} else if (topIndex > lineCount - pageSize) {		topIndex = lineCount - pageSize;	}	int pixel = getLinePixel(topIndex) + verticalScrollOffset;	setVerticalScrollOffset(pixel, true);}