Handle nested position:sticky elements correctly (compositor)

third_party/WebKit/LayoutTests/compositing/overflow/composited-nested-sticky-deep-expected.html

Index: third_party/WebKit/LayoutTests/compositing/overflow/composited-nested-sticky-deep-expected.html
diff --git a/third_party/WebKit/LayoutTests/compositing/overflow/composited-nested-sticky-deep-expected.html b/third_party/WebKit/LayoutTests/compositing/overflow/composited-nested-sticky-deep-expected.html
new file mode 100644
index 0000000000000000000000000000000000000000..fb8b67cd72c4eeedb8010975482e7d88375ce07e
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/compositing/overflow/composited-nested-sticky-deep-expected.html
@@ -0,0 +1,73 @@
+<style>
+body {
+  margin: 0;
+}
+
+.scroller {
+  overflow: auto;
+  width: 200px;
+  height: 500px;
+  outline: 2px solid black;
+}
+
+.container {
+  width: 200px;
+  height: 1000px;
+}
+
+.first {
+  position: relative;
+  top: 400px;
+  height: 100px;
+  width: 200px;
+  background-color: green;
+}
+
+.second {
+  position: relative;
+  top: 400px;
+  height: 100px;
+  width: 200px;
+  background-color: yellow;
+}
+
+.third {
+  position: relative;
+  top: 400px;
+  height: 100px;
+  width: 200px;
+  background-color: pink;
+}
+
+.fourth {
+  position: relative;
+  top: 400px;
+  height: 100px;
+  width: 200px;
+  background-color: blue;
+}
+
+.fifth {
+  position: relative;
+  top: 400px;
+  height: 100px;
+  width: 200px;
+  background-color: red;
+}
+</style>
+
+<script>
+window.addEventListener('load', function() {
+  document.querySelector('.scroller').scrollTop = 400;
+});
+</script>
+
+<div class="scroller">
+  <div class="container">
+    <div class="first"></div>
+    <div class="second"></div>
+    <div class="third"></div>
+    <div class="fourth"></div>
+    <div class="fifth"></div>
+  </div>
+</div>