Show tooltip to overflowed grid cell.

If the content of the cell do not fit in its visible part, I want to show tooltip with the full text of this cell and if its not don't show it. Any ideas how can I do it ?

```
// think about smth like this
// but don't know how to get content width

text: 'someHeaderName',
listeners: {
    resize( th, newWidth, height, oldWidth, oldHeight, eOpts ) {
        if (newWidth <= contentWidth) {
            this.showTooltip = true;
            th.up('panel').getView().refresh();
        }
    }
},
renderer: function(val, meta, rec, rowIndex, colIndex, store, view) {
    if (this.showTooltip) {
        meta.tdAttr = 'data-qtip="' + val + '"';
    }
    return val;
}

```