title: How to center icon in a MaterialButton which has no text?
body: <p>I'm using the latest version of the <code>com.google.android.material:material</code> library (i.e. <code>1.1.0-alpha03</code>) and I have a <code>MaterialButton</code> defined with an icon and no text as follows:</p>
  
  <p></p>
  
  <p>I was hoping the <code>MaterialButton</code> would be rendered as a square with the icon centred within it but instead the <code>MaterialButton</code> is rendered as follows:</p>
  
  <p><a href="https://i.stack.imgur.com/kRUrj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/kRUrj.png" alt="MaterialButton with iconGravity value of start"></a></p>
  
  <p>If I change the <code>iconGravity</code> value to <code>"textStart"</code> the <code>MaterialButton</code> is rendered as follows:</p>
  
  <p><a href="https://i.stack.imgur.com/rnuz5.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rnuz5.png" alt="MaterialButton with iconGravity value of textStart"></a></p>
  
  <p>This is a slight improvement to the positioning of the icon but the icon is still a little off centre. If I change the <code>insetLeft</code>, <code>insetRight</code>, <code>insetTop</code> and <code>insetBottom</code> values to <code>0dp</code> the <code>MaterialButton</code> is rendered as follows:</p>
  
  <p><a href="https://i.stack.imgur.com/Ihjqc.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Ihjqc.png" alt="enter image description here"></a></p>
  
  <p>This is an improvement to the shape of the button but the icon is still a little off centre.</p>
  
  <p>Anyone know whether there's something further I can do to centre the icon within the <code>MaterialButton</code>?</p>