Change layerTreeAsText to default to layer lists.

third_party/WebKit/LayoutTests/csspaint/resources/test-runner-invalidation-logging.js

 // Test runner for the paint worklet to test invalidation behaviour.
 //
 // Registers an promise_test per test case, which:
 //  - Creates an element.
 //  - Invalidates the style of that element.
 //  - [worklet] Worklet code logs if it got the invalidation.
 //  - Asserts that it got the correct paint invalidation.
 //
 // Usage:
 // testRunnerInvalidationLogging('background-image', [
@@ skipping 59 matching lines @@
                 if (test.invalidationProperty) {
                     el.style.setProperty(test.invalidationProperty, test.value);
                 } else {
                     el.style.setProperty(test.property, test.value);
                 }
 
                 runAfterLayoutAndPaint(function() {
                     // Check that the we got the correct paint invalidation.
                     if (window.internals) {
                         const layers = JSON.parse(internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_PAINT_INVALIDATIONS));
-                        const paintInvalidations = layers['children'][0]['paintInvalidations'];
+                        const paintInvalidations = layers['layers'][0]['paintInvalidations'];
                         assert_equals(!paintInvalidations, !!test.noInvalidation);
                         if (paintInvalidations) {
                             assert_equals(paintInvalidations.length, 1, 'There should be only one paint invalidation.');
                             assert_array_equals(
                                     paintInvalidations[0]['rect'],
                                     [rect.left, rect.top, rect.width, rect.height],
                                     'The paint invalidation should cover the entire element.');
                         }
                         internals.stopTrackingRepaints(document);
                     }
 
                     // Cleanup.
                     document.body.removeChild(el);
                     resolve();
                 });
             });
 
         });
 
     }, testName);
 }