title: How to get refs element in scoped slot
body: <p>If there are some refs in slot's template, how can I access these refs from the component? For example:</p>
  
  <h2>v-component.vue</h2>
  
  <pre><code>&lt;template&gt;
      &lt;div&gt;
          &lt;slot&gt;&lt;/slot&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  &lt;script&gt;
     export default {
         created() {
             console.log(this.$refs.ele)
         }
     }
  &lt;/script&gt;
  </code></pre>
  
  <h2>app.vue</h2>
  
  <pre><code>&lt;template&gt;
      &lt;v-component&gt;
         &lt;template slot-scope="props"&gt;
            &lt;h1 ref="ele"&gt;&lt;/h1&gt;
         &lt;/template&gt;
      &lt;/v-component&gt;
  &lt;/template&gt;
  &lt;script&gt;
     import VComponent from './v-component
     export default {
         components: { VComponent }
     }
  &lt;/script&gt;
  </code></pre>
  
  <p>this.$refs.ele in v-compoent.vue output undefined. My question is how can I get this element?</p>