<!DOCTYPE html>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<script>
  if (window.internals)
    internals.settings.setScrollAnimatorEnabled(false);
</script>
<style>
  ::-webkit-scrollbar {
    width: 0px;
    height: 0px;
  }

  body, html {
    width: 100%;
    height: 100%;
    margin: 0;
  }

  #rootscroller {
    width: 100%;
    height: 100%;
    overflow: auto;
    position: absolute;
    left: 0;
    top: 0;
    z-index: -1;
    background-color: red;
  }

  .spacer {
    width: 200%;
    height: 200%;
  }

  #inflow {
    width: 200%;
    height: 200%;
    background-color: lightgreen;
    z-index: 1;
  }
</style>

<div id="rootscroller">
  <div class="spacer">
  </div>
</div>

<!--This element overflows the viewport and appears over the root scroller.
    Therefore, scrolling it should scroll the document rather than the root
    scroller -->
<div id="inflow">
  This test ensures that when the document is not the root scroller, i.e.
  another element has been set as document.rootScroller, it can still be
  scrolled via the keyboard.
</div>

<script>
  function click(x, y) {
    return new Promise((resolve, reject) => {
      var pointerActions =
              [{source: "mouse",
                actions: [
                  { name: "pointerMove", x: x, y: y },
                  { name: "pointerDown", x: x, y: y, button: 'left'},
                  { name: "pointerUp", x: x, y: y, button: 'left' }]}];
      chrome.gpuBenchmarking.pointerActionSequence(pointerActions, resolve);
    });
  }

  window.onload = function() {
    var rootscroller = document.querySelector('#rootscroller');
    document.rootScroller = rootscroller;

    promise_test( t => {
      // Ensure the "inflow" element/document is focused to receive keyboard
      // events.
      return click(100, 100).then( () => {
        if (window.internals) {
          assert_equals(internals.effectiveRootScroller(document),
                        rootscroller,
                        "Failed to set root scroller");
        }
        eventSender.keyDown('ArrowDown');

        assert_greater_than(
            document.scrollingElement.scrollTop, 0, "Document must be scrolled");
        assert_equals(
            rootscroller.scrollTop, 0, "RootScroller must not be scrolled");
      })
    }, "Arrow keys should scroll document.");
  }
</script>