<Button xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Button.Background>
  <x:Null/>
</Button.Background>
<Button.Height>
  <x:Static Member="SystemParameters.IconHeight"/>
</Button.Height>
<Button.Content>
  <Binding Path="Height">
  <Binding.RelativeSource>
    <RelativeSource Mode="Self"/>
  </Binding.RelativeSource>
  </Binding>
</Button.Content>
</Button>