title: Use style/theme colour on a vector asset
body: <p>Hi i am trying to set a fillcolour to use the theme/style of colorOnPrimary</p>
  <p>via <code> android:fillColor=&quot;?colorOnPrimary&quot;</code></p>
  <p>However i get this  error:  <code>Invalid color value ?colorOnPrimary</code> when i try and build my project</p>
  <p>This is what my vector asset xml looks like:</p>
  <pre><code>&lt;vector xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
      android:width=&quot;18dp&quot;
      android:height=&quot;18dp&quot;
      android:viewportWidth=&quot;18&quot;
      android:viewportHeight=&quot;18&quot;&gt;
      &lt;path
          android:fillColor=&quot;?colorOnPrimary&quot;
          android:fillType=&quot;evenOdd&quot;
          android:pathData=&quot;....&quot; /&gt;
  &lt;/vector&gt;
  </code></pre>