Moving AXNode.language_info_ from raw pointer to unique_ptr

R=dmazzoni,aboxhall
BUG=889370

Change-Id: Ic3cb08d971a387fe55fe9b6c527eaab09db18dd5
Reviewed-on: https://chromium-review.googlesource.com/c/1354734
Commit-Queue: Chris Hall <chrishall@chromium.org>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612992}

ui/accessibility/ax_node.cc

@@ -28,10 +28,7 @@ AXNode::AXNode(AXNode::OwnerTree* tree,
   data_.id = id;
 }
 
-AXNode::~AXNode() {
-  if (language_info_)
-    delete language_info_;
-}
+AXNode::~AXNode() = default;
 
 int AXNode::GetUnignoredChildCount() const {
   int count = 0;
@@ -184,15 +181,15 @@ base::string16 AXNode::GetInheritedString16Attribute(
 
 const AXLanguageInfo* AXNode::GetLanguageInfo() {
   if (language_info_)
-    return language_info_;
+    return language_info_.get();
 
   const auto& lang_attr =
       GetStringAttribute(ax::mojom::StringAttribute::kLanguage);
 
   // Promote language attribute to LanguageInfo.
   if (!lang_attr.empty()) {
-    language_info_ = new AXLanguageInfo(this, lang_attr);
-    return language_info_;
+    language_info_.reset(new AXLanguageInfo(this, lang_attr));
+    return language_info_.get();
   }
 
   // Try search for language through parent instead.
@@ -204,8 +201,8 @@ const AXLanguageInfo* AXNode::GetLanguageInfo() {
     return nullptr;
 
   // Cache the results on this node.
-  language_info_ = new AXLanguageInfo(parent_lang_info, this);
-  return language_info_;
+  language_info_.reset(new AXLanguageInfo(parent_lang_info, this));
+  return language_info_.get();
 }
 
 std::string AXNode::GetLanguage() {

ui/accessibility/ax_node.h

@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <ostream>
 #include <vector>
 
@@ -283,7 +284,7 @@ class AX_EXPORT AXNode final {
   std::vector<AXNode*> children_;
   AXNodeData data_;
 
-  AXLanguageInfo* language_info_;
+  std::unique_ptr<AXLanguageInfo> language_info_;
 
   // Return an object containing information about the languages used.
   // Will walk up tree if needed to determine language.