Refactor out some repeated code in WebAXObjectProxy

Bug: none
Change-Id: If156da0fe3fb65e99ad00984cf65c0b962a6bbf8
AX-Relnotes: N/A
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2438732
Auto-Submit: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Meredith Lane <meredithl@chromium.org>
Reviewed-by: Meredith Lane <meredithl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811914}

content/web_test/renderer/web_ax_object_proxy.h

@@ -61,6 +61,9 @@ class WebAXObjectProxy : public gin::Wrappable<WebAXObjectProxy> {
  private:
   friend class WebAXObjectProxyBindings;
 
+  void UpdateLayout();
+  ui::AXNodeData GetAXNodeData() const;
+
   // Bound properties.
   std::string Role();
   std::string StringValue();