public Builder clearHtmlAdResource() {
      if (htmlAdResourceBuilder_ == null) {
        if (adResourceCase_ == 12) {
          adResourceCase_ = 0;
          adResource_ = null;
          onChanged();
        }
      } else {
        if (adResourceCase_ == 12) {
          adResourceCase_ = 0;
          adResource_ = null;
        }
        htmlAdResourceBuilder_.clear();
      }
      return this;
    }
<pre>
The HTML ad resource associated with the companion ad.
</pre>

<code>.google.cloud.video.stitcher.v1.HtmlAdResource html_ad_resource = 12;</code>
java-video-stitcher/proto-google-cloud-video-stitcher-v1/src/main/java/com/google/cloud/video/stitcher/v1/Companion.java