Change layerTreeAsText to default to layer lists.

third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html

Index: third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html
diff --git a/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html
index 34d8fff8f606940fdfca18965daf26d65e3e2d6f..ebfc88a115c3c4adf67e76d8f6d73286f27250b5 100644
--- a/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html
+++ b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-background-opaque-to-transparent.html
@@ -1,4 +1,5 @@
 <script src="../../resources/run-after-layout-and-paint.js"></script>
+<script src="resources/composited-scroll.js"></script>
 <script>
     if (window.internals)
         internals.runtimeFlags.compositeOpaqueScrollersEnabled = true;
@@ -8,30 +9,6 @@
         testRunner.waitUntilDone();
     }
 
-    function hasOpaqueCompositedScrollingContentsLayer(layer) {
-        if (layer.name == "Scrolling Contents Layer")
-            return layer.contentsOpaque;
-        if (layer.children) {
-            for (var i = 0; i < layer.children.length; i++) {
-                if (hasOpaqueCompositedScrollingContentsLayer(layer.children[i]))
-                    return true;
-            }
-        }
-        return false;
-    }
-
-    function hasCompositedScrollingContentsLayer(layer) {
-        if (layer.name == "Scrolling Contents Layer")
-            return true;
-        if (layer.children) {
-            for (var i = 0; i < layer.children.length; i++) {
-                if (hasCompositedScrollingContentsLayer(layer.children[i]))
-                    return true;
-            }
-        }
-        return false;
-    }
-
     onload = function() {
         if (!window.testRunner || !window.internals)
             return;
@@ -48,7 +25,7 @@
 
         runAfterLayoutAndPaint(function() {
             var result = "Should not have opaque composited scrolling contents layer: ";
-            if (!hasCompositedScrollingContentsLayer(JSON.parse(window.internals.layerTreeAsText(document))))
+            if (!isUsingCompositedScrolling(JSON.parse(window.internals.layerTreeAsText(document))))
                 result += "Pass.\n";
             else
                 result += "Fail.\n";