Remove more usage of the base::ListValue::Append(Value*) overload.

content/browser/accessibility/accessibility_tree_formatter.cc

 // Copyright (c) 2012 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 "content/browser/accessibility/accessibility_tree_formatter.h"
 
 #include <stddef.h>
 
 #include <memory>
+#include <utility>
 
 #include "base/logging.h"
+#include "base/memory/ptr_util.h"
 #include "base/strings/pattern.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents.h"
 
@@ skipping 32 matching lines @@
 
 void AccessibilityTreeFormatter::RecursiveBuildAccessibilityTree(
     const BrowserAccessibility& node, base::DictionaryValue* dict) {
   AddProperties(node, dict);
 
   base::ListValue* children = new base::ListValue;
   dict->Set(kChildrenDictAttr, children);
 
   for (size_t i = 0; i < ChildCount(node); ++i) {
     BrowserAccessibility* child_node = GetChild(node, i);
-    base::DictionaryValue* child_dict = new base::DictionaryValue;
-    children->Append(child_dict);
-    RecursiveBuildAccessibilityTree(*child_node, child_dict);
+    std::unique_ptr<base::DictionaryValue> child_dict(
+        new base::DictionaryValue);
+    RecursiveBuildAccessibilityTree(*child_node, child_dict.get());

[danakj, 2016/08/27 00:07:14]

Wait.. doesn't this change the order. Now we recurse then append. So the first
child will become the last?

[dcheng, 2016/08/30 06:47:48]

No, the recursive call builds the child node, which we then append here.
Everything is still appended in the same order, since the actual child append
takes place in this loop.

[danakj, 2016/09/06 21:55:39]

Oh ya ok, you right. Children will not see themselves in the |children| list
anymore. But that's local so seems okay.

+    children->Append(std::move(child_dict));
   }
 }
 
 void AccessibilityTreeFormatter::RecursiveFormatAccessibilityTree(
     const base::DictionaryValue& dict, base::string16* contents, int depth) {
   base::string16 indent = base::string16(depth * kIndentSymbolCount,
                                          kIndentSymbol);
   base::string16 line = indent + ToString(dict);
   if (line.find(base::ASCIIToUTF16(kSkipString)) != base::string16::npos)
     return;
@@ skipping 73 matching lines @@
   if (attr.empty())
     return;
   if (!MatchesFilters(attr, include_by_default))
     return;
   if (!line->empty())
     *line += base::ASCIIToUTF16(" ");
   *line += attr;
 }
 
 }  // namespace content