title: Why does angular-material strip all classes off md-button?
body: <p>My code:</p>
  
  <pre><code>&lt;md-button class="md-raised md-primary"&gt;Login&lt;/md-button&gt;
  </code></pre>
  
  <p>But Chrome renders it as:</p>
  
  <pre><code>&lt;button class="md-button md-default-theme" ng-transclude="" style="touch-action: pan-y; -webkit-user-select: none; -webkit-user-drag: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);"&gt;&lt;span class="ng-scope"&gt;Login&lt;/span&gt;&lt;/button&gt;
  </code></pre>
  
  <p>The classes .md-raised and .md-primary have been stripped even though the source code example in the official tutorials state to use them.</p>