Correct const accessors in base/values.(h|cc), Part II (ListValue)

chrome/browser/extensions/webstore_install_helper.cc

Index: chrome/browser/extensions/webstore_install_helper.cc
diff --git a/chrome/browser/extensions/webstore_install_helper.cc b/chrome/browser/extensions/webstore_install_helper.cc
index f1960b589a3425551c6fafec9d9b9153a4f15527..950fbb6132e518d5bd84237f09c90d9286b5c9be 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -152,11 +152,11 @@ void WebstoreInstallHelper::OnDecodeImageFailed() {
 void WebstoreInstallHelper::OnJSONParseSucceeded(const ListValue& wrapper) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   manifest_parse_complete_ = true;
-  Value* value = NULL;
+  const Value* value = NULL;
   CHECK(wrapper.Get(0, &value));
   if (value->IsType(Value::TYPE_DICTIONARY)) {
     parsed_manifest_.reset(
-        static_cast<DictionaryValue*>(value)->DeepCopy());
+        static_cast<const DictionaryValue*>(value)->DeepCopy());
   } else {
     parse_error_ = Delegate::MANIFEST_ERROR;
   }