Paint local attachment backgrounds into composited scrolling contents layer

third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html

Index: third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html
diff --git a/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html
index 6dc6ab4a3803926001355062c47b297730883a16..f182e2c8cfa11444e20f3bcd84f7579f762933b3 100644
--- a/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html
+++ b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-local-background.html
@@ -5,7 +5,8 @@ onload = function() {
     // Double rAF to ensure content is painted before scroll.

[chrishtr, 2016/08/12 17:03:00]

Add another test rather than modifying this one.

[flackr, 2016/08/16 17:52:51]

Done.

     requestAnimationFrame(function() {
         requestAnimationFrame(function() {
-            document.getElementById('scroller').scrollTo(0, 200);
+            document.getElementById('scroller1').scrollTop = 200;
+            document.getElementById('scroller2').scrollTop = 200;
             if (window.testRunner)
                 window.testRunner.notifyDone();
         })
@@ -13,8 +14,7 @@ onload = function() {
 }
 </script>
 <style>
-#scroller {
-    background: gray local content-box;
+.scroller {
     border: 10px solid rgba(0, 255, 0, 0.5);
     overflow: scroll;
     padding: 10px;
@@ -23,6 +23,14 @@ onload = function() {
     will-change: transform;
 }
 
+#scroller1 {
+    background: gray local content-box;
+}
+
+#scroller2 {
+    background: url('../resources/apple.jpg') local;
+}
+
 .spacer {
     height: 300px;
 }
@@ -32,6 +40,11 @@ onload = function() {
     element without repainting requires the background to be painted into
     the scrolling contents layer and correctly account for that layer not
     including the border in its bounds. -->
-<div id="scroller">
+<div id="scroller1" class="scroller">
+    <div class="spacer"></div>
+</div>
+<!-- This scroller has a locally attached background image which should
+    scroll with the content. -->
+<div id="scroller2" class="scroller">
     <div class="spacer"></div>
 </div>