Fix padding in headerbar

[Jorge Toledo]

The padding around buttons in the headerbar is not uniform. There's either too much top/bottom padding or not enough right/left padding; especially noticeable around the close/maximize buttons.

See screenshot: current design (top) and proposal (bottom).

[Jacob Parker (jacobparker1992)]

Extra padding is there to make it easier to drag the window.

[Raphael Isemann (teemperor)]

I think he means that there should be a uniform padding for all elements as it is currently a bit off if i see that correctly.

[Jorge Toledo (eldelacajita)]

I meant exactly that, Raphael.

BTW, I forgot to mention that this bug only affects Freya Beta 1.

[Danielle Foré (danrabbit)]

So the problem is that the HeaderBar gets its height based on padding. There is no way to set a minimum height or directly set the height and there is no way to set margins from the theme. That means depending on what kind of widgets the app packs into a HeaderBar, it can be a different height. So it's not really possible to ensure that the margin will always be equal all the way around window decorations buttons.