Revert of Add fuzzer for AXTree and fix a couple of bugs it found.

ui/accessibility/ax_tree_fuzzer.cc

-// Copyright 2016 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 "ui/accessibility/ax_tree.h"
-
-class EmptyAXTreeDelegate : public ui::AXTreeDelegate {
- public:
-  EmptyAXTreeDelegate() {}
-
-  void OnNodeDataWillChange(ui::AXTree* tree,
-                            const ui::AXNodeData& old_node_data,
-                            const ui::AXNodeData& new_node_data) override {}
-  void OnTreeDataChanged(ui::AXTree* tree) override {}
-  void OnNodeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnSubtreeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnNodeWillBeReparented(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnSubtreeWillBeReparented(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnNodeCreated(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnNodeReparented(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnNodeChanged(ui::AXTree* tree, ui::AXNode* node) override {}
-  void OnAtomicUpdateFinished(ui::AXTree* tree,
-                              bool root_changed,
-                              const std::vector<Change>& changes) override {}
-};
-
-// Entry point for LibFuzzer.
-extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data, size_t size) {
-  ui::AXTreeUpdate initial_state;
-  size_t i = 0;
-  while (i < size) {
-    ui::AXNodeData node;
-    node.id = data[i++];
-    node.state = 0;
-    if (i < size) {
-      size_t child_count = data[i++];
-      for (size_t j = 0; j < child_count && i < size; j++)
-        node.child_ids.push_back(data[i++]);
-    }
-    initial_state.nodes.push_back(node);
-  }
-
-  // Run with --v=1 to aid in debugging a specific crash.
-  VLOG(1) << "Input accessibility tree:\n" << initial_state.ToString();
-
-  ui::AXTree tree;
-  EmptyAXTreeDelegate delegate;
-  tree.SetDelegate(&delegate);
-  tree.Unserialize(initial_state);
-
-  return 0;
-}