clip-content-under-overflow-controls.html

<!DOCTYPE html>
<!DOCTYPE html>
<style>
.composited {
  will-change: transform;
}

.container {
  width:100px;
  height:100px;
  overflow:scroll;
  resize:both;
  position:absolute;
}

.container::-webkit-scrollbar {
  background-color: rgba(0, 127, 0, 0.5);
}
.container::-webkit-resizer {
  background-color: rgba(0, 127, 0, 0.5);
}

.normalContentArea {
  background-color: rgba(0, 127, 0, 0.5);
  position:absolute;
  top:0px;
  bottom:0px;
  left:0px;
  right:0px
}

.beneathVerticalScrollbar {
  position:absolute;
  background-color: red;
  bottom:-15px;
  left:0px;
  right:0px;
  height:15px;
}

.beneathHorizontalScrollbar {
  position:absolute;
  background-color: red;
  top:0px;
  bottom:0px;
  right:-15px;
  width:15px;
}

.beneathScrollCorner {
  position:absolute;
  background-color: red;
  bottom:-15px;
  right:-15px;
  height:15px;
  width:15px;
}
</style>
<!-- No red should be visible, only a solid green square. -->
<div class="container composited">
  <div class="normalContentArea"></div>
  <div class="beneathVerticalScrollbar"></div>
  <div class="beneathHorizontalScrollbar"></div>
  <div class="beneathScrollCorner"></div>
</div>

chromium/third_party/blink/web_tests/compositing/overflow/clip-content-under-overflow-controls.html