A11y: Add/refactor methods for manipulating bitfields on AXNodeData.

ui/accessibility/ax_tree.cc

Index: ui/accessibility/ax_tree.cc
diff --git a/ui/accessibility/ax_tree.cc b/ui/accessibility/ax_tree.cc
index c726a4d02f5e4b0b75035a92bd4e647b6f8bd4f3..2dcf61eab6284a3f573561dd61b16a0a204b0246 100644
--- a/ui/accessibility/ax_tree.cc
+++ b/ui/accessibility/ax_tree.cc
@@ -128,6 +128,7 @@ AXTree::AXTree()
     : delegate_(NULL), root_(NULL) {
   AXNodeData root;
   root.id = -1;
+  root.ClearBitfields();
 
   AXTreeUpdate initial_state;
   initial_state.root_id = -1;
@@ -360,10 +361,8 @@ void AXTree::CallNodeChangeCallbacks(AXNode* node, const AXNodeData& new_data) {
   if (old_data.state != new_data.state) {
     for (int i = AX_STATE_NONE + 1; i <= AX_STATE_LAST; ++i) {
       AXState state = static_cast<AXState>(i);
-      if (old_data.HasStateFlag(state) != new_data.HasStateFlag(state)) {
-        delegate_->OnStateChanged(this, node, state,
-                                  new_data.HasStateFlag(state));
-      }
+      if (old_data.HasState(state) != new_data.HasState(state))
+        delegate_->OnStateChanged(this, node, state, new_data.HasState(state));
     }
   }