Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/generated_message_util.cc

Index: third_party/protobuf/src/google/protobuf/generated_message_util.cc
diff --git a/third_party/protobuf/src/google/protobuf/generated_message_util.cc b/third_party/protobuf/src/google/protobuf/generated_message_util.cc
index 683a9d5c738c7c81ce9d2d03dc284844d773ed89..334051a013e4098afea6eed399a54caae30ac729 100644
--- a/third_party/protobuf/src/google/protobuf/generated_message_util.cc
+++ b/third_party/protobuf/src/google/protobuf/generated_message_util.cc
@@ -48,13 +48,15 @@ double NaN() {
   return std::numeric_limits<double>::quiet_NaN();
 }
 
-ExplicitlyConstructed< ::std::string> fixed_address_empty_string;
+const ::std::string* empty_string_;
 GOOGLE_PROTOBUF_DECLARE_ONCE(empty_string_once_init_);
 
-void DeleteEmptyString() { fixed_address_empty_string.Shutdown(); }
+void DeleteEmptyString() {
+  delete empty_string_;
+}
 
 void InitEmptyString() {
-  fixed_address_empty_string.DefaultConstruct();
+  empty_string_ = new string;
   OnShutdown(&DeleteEmptyString);
 }
 
@@ -77,10 +79,6 @@ int StringSpaceUsedExcludingSelf(const string& str) {
 
 
 
-void InitProtobufDefaults() {
-  GetEmptyString();
-}
-
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google