detect preferences errors

BUG=38352
TEST=none

Review URL: http://codereview.chromium.org/1120006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43715 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/common/extensions/extension_unpacker.cc b/chrome/common/extensions/extension_unpacker.cc
index ae2e0e3..dad10f4 100644
--- a/chrome/common/extensions/extension_unpacker.cc
+++ b/chrome/common/extensions/extension_unpacker.cc
@@ -101,7 +101,7 @@
 
   JSONFileValueSerializer serializer(manifest_path);
   std::string error;
-  scoped_ptr<Value> root(serializer.Deserialize(&error));
+  scoped_ptr<Value> root(serializer.Deserialize(NULL, &error));
   if (!root.get()) {
     SetError(error);
     return NULL;
@@ -281,7 +281,7 @@
   std::string error;
   JSONFileValueSerializer serializer(message_path);
   scoped_ptr<DictionaryValue> root(
-      static_cast<DictionaryValue*>(serializer.Deserialize(&error)));
+      static_cast<DictionaryValue*>(serializer.Deserialize(NULL, &error)));
   if (!root.get()) {
     std::string messages_file = WideToASCII(message_path.ToWStringHack());
     if (error.empty()) {