third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/io/gzip_stream.cc

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
@@ skipping 150 matching lines @@
   }
   DoNextOutput(data, size);
   return true;
 }
 void GzipInputStream::BackUp(int count) {
   output_position_ = reinterpret_cast<void*>(
       reinterpret_cast<uintptr_t>(output_position_) - count);
 }
 bool GzipInputStream::Skip(int count) {
   const void* data;
-  int size;
+  int size = 0;
   bool ok = Next(&data, &size);
   while (ok && (size < count)) {
     count -= size;
     ok = Next(&data, &size);
   }
   if (size > count) {
     BackUp(size - count);
   }
   return ok;
 }
@@ skipping 139 matching lines @@
   bool ok = zerror_ == Z_OK;
   zerror_ = Z_STREAM_END;
   return ok;
 }
 
 }  // namespace io
 }  // namespace protobuf
 }  // namespace google
 
 #endif  // HAVE_ZLIB