Refactor BrowserAccessibility to prepare for AXNode (re-land)

content/browser/accessibility/browser_accessibility_manager_gtk.cc

Index: content/browser/accessibility/browser_accessibility_manager_gtk.cc
diff --git a/content/browser/accessibility/browser_accessibility_manager_gtk.cc b/content/browser/accessibility/browser_accessibility_manager_gtk.cc
index 3d7a97658f41c67ea2f1fbb84d8cd5439798cdc4..8748de57fefc47e0574ebb32659cec8ed2154fb2 100644
--- a/content/browser/accessibility/browser_accessibility_manager_gtk.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_gtk.cc
@@ -68,9 +68,9 @@ void BrowserAccessibilityManagerGtk::NotifyAccessibilityEvent(
 void BrowserAccessibilityManagerGtk::RecursivelySendChildrenChanged(
     BrowserAccessibilityGtk* node) {
   AtkObject* atkObject = node->ToBrowserAccessibilityGtk()->GetAtkObject();
-  for (unsigned int i = 0; i < node->children().size(); ++i) {
+  for (unsigned int i = 0; i < node->InternalChildCount(); ++i) {
     BrowserAccessibilityGtk* child =
-        node->children()[i]->ToBrowserAccessibilityGtk();
+        node->InternalGetChild(i)->ToBrowserAccessibilityGtk();
     g_signal_emit_by_name(atkObject,
                           "children-changed::add",
                           i,