Fix a leak in JSONParser::Parse when using hidden root optimizations.

base/json/json_parser.cc

Index: base/json/json_parser.cc
diff --git a/base/json/json_parser.cc b/base/json/json_parser.cc
index 766c764a2c4c4ae0239e48a0f3afdf2fa02aa728..d1bba4464b1dfd6ee6d9f891bca8312b8c09adb3 100644
--- a/base/json/json_parser.cc
+++ b/base/json/json_parser.cc
@@ -258,9 +258,9 @@ Value* JSONParser::Parse(const std::string& input) {
   // hidden root.
   if (!(options_ & JSON_DETACHABLE_CHILDREN)) {
     if (root->IsType(Value::TYPE_DICTIONARY)) {
-      return new DictionaryHiddenRootValue(&input_copy, root.release());
+      return new DictionaryHiddenRootValue(&input_copy, root.get());
     } else if (root->IsType(Value::TYPE_LIST)) {
-      return new ListHiddenRootValue(&input_copy, root.release());
+      return new ListHiddenRootValue(&input_copy, root.get());
     } else if (root->IsType(Value::TYPE_STRING)) {
       // A string type could be a JSONStringValue, but because there's no
       // corresponding HiddenRootValue, the memory will be lost. Deep copy to