ax_dump_tree: exclude children attribute from formatted tree on mac

children attribute represents a dictionary containing whole subtree, ax_dump_tree tool navigates the hierarchy on its own, what makes children unnecessary and the output bulky

Bug: 1124366
Change-Id: Icd77ff5c8bdc163971855695500469d4b3ba92d9
AX-Relnotes: n/a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412192Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Alexander Surkov <asurkov@igalia.com>
Cr-Commit-Position: refs/heads/master@{#808712}

tools/accessibility/inspect/ax_tree_server.cc

@@ -81,8 +81,14 @@ void AXTreeServer::Run(BuildTree build_tree,
 std::vector<AccessibilityTreeFormatter::PropertyFilter>
 AXTreeServer::GetPropertyFilters(const base::FilePath& filters_path) {
   if (filters_path.empty()) {
-    return {AccessibilityTreeFormatter::PropertyFilter(
-        "*", AccessibilityTreeFormatter::PropertyFilter::ALLOW)};
+    return {
+      AccessibilityTreeFormatter::PropertyFilter(
+          "*", AccessibilityTreeFormatter::PropertyFilter::ALLOW),
+#if defined(OS_MAC)
+      AccessibilityTreeFormatter::PropertyFilter(
+          "children", AccessibilityTreeFormatter::PropertyFilter::DENY),
+#endif
+    };
   }
 
   std::string raw_filters_text;