Protobuf: Cherry-pick upstream r427.

third_party/protobuf/src/google/protobuf/descriptor.cc

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // http://code.google.com/p/protobuf/
 //
 // 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 2338 matching lines @@
   // defined in multiple parent scopes, we only want to find "Bar.baz" in the
   // innermost one.  E.g., the following should produce an error:
   //   message Bar { message Baz {} }
   //   message Foo {
   //     message Bar {
   //     }
   //     optional Bar.Baz baz = 1;
   //   }
   // So, we look for just "Foo" first, then look for "Bar.baz" within it if
   // found.
-  int name_dot_pos = name.find_first_of('.');
+  string::size_type name_dot_pos = name.find_first_of('.');
   string first_part_of_name;
   if (name_dot_pos == string::npos) {
     first_part_of_name = name;
   } else {
     first_part_of_name = name.substr(0, name_dot_pos);
   }
 
   string scope_to_try(relative_to);
 
   while (true) {
@@ skipping 2118 matching lines @@
       break;
 
     default:
       GOOGLE_LOG(FATAL) << "Invalid wire type for CPPTYPE_UINT64: " << type;
       break;
   }
 }
 
 }  // namespace protobuf
 }  // namespace google