DevTools: Replace visibleChildrenCount with hasVisibleChildren in ElementsTreeOutline.

LayoutTests/http/tests/inspector/elements-test.js

Index: LayoutTests/http/tests/inspector/elements-test.js
diff --git a/LayoutTests/http/tests/inspector/elements-test.js b/LayoutTests/http/tests/inspector/elements-test.js
index 7a4ccd533cef6ab68c103f8d6e4ddc332678ca85..8539fa118b3806e8a97d73e949c871923f04125d 100644
--- a/LayoutTests/http/tests/inspector/elements-test.js
+++ b/LayoutTests/http/tests/inspector/elements-test.js
@@ -21,7 +21,9 @@ InspectorTest.findNode = function(matchFunction, callback)
             if (result)
                 return;
 
-            var children = (node.children() || []).concat(node.shadowRoots()).concat(Object.values(node.pseudoElements() || {}));
+            var pseudoElementsMap = node.pseudoElements();
+            var pseudoElements = pseudoElementsMap ? pseudoElementsMap.valuesArray() : [];
+            var children = (node.children() || []).concat(node.shadowRoots()).concat(pseudoElements);
             if (node.templateContent())
                 children.push(node.templateContent());
             else if (node.importedDocument())