Add a treeChange type to Automation

ui/accessibility/platform/test_ax_node_wrapper.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/containers/hash_tables.h"
 #include "ui/accessibility/platform/test_ax_node_wrapper.h"
 
 namespace ui {
 
 namespace {
 
 // A global map from AXNodes to TestAXNodeWrappers.
 base::hash_map<AXNode*, TestAXNodeWrapper*> g_node_to_wrapper_map;
 
 // A global coordinate offset.
 gfx::Vector2d g_offset;
 
 // A simple implementation of AXTreeDelegate to catch when AXNodes are
 // deleted so we can delete their wrappers.
 class TestAXTreeDelegate : public AXTreeDelegate {
+  void OnNodeDataWillChange(AXTree* tree,
+                            const AXNodeData& old_node_data,
+                            const AXNodeData& new_node_data) override {}
   void OnTreeDataChanged(AXTree* tree) override {}
   void OnNodeWillBeDeleted(AXTree* tree, AXNode* node) override {
     auto iter = g_node_to_wrapper_map.find(node);
     if (iter != g_node_to_wrapper_map.end()) {
       TestAXNodeWrapper* wrapper = iter->second;
       delete wrapper;
       g_node_to_wrapper_map.erase(iter->first);
     }
   }
   void OnSubtreeWillBeDeleted(AXTree* tree, AXNode* node) override {}
@@ skipping 82 matching lines @@
   return false;
 }
 
 TestAXNodeWrapper::TestAXNodeWrapper(AXTree* tree, AXNode* node)
     : tree_(tree),
       node_(node),
       platform_node_(AXPlatformNode::Create(this)) {
 }
 
 }  // namespace ui