Update protobuf to r428, part 1.

third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_generator.cc

Index: third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_generator.cc
===================================================================
--- third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_generator.cc	(revision 216642)
+++ third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_generator.cc	(working copy)
@@ -78,11 +78,13 @@
   //   }
   // FOO_EXPORT is a macro which should expand to __declspec(dllexport) or
   // __declspec(dllimport) depending on what is being compiled.
-  string dllexport_decl;
+  Options file_options;
 
   for (int i = 0; i < options.size(); i++) {
     if (options[i].first == "dllexport_decl") {
-      dllexport_decl = options[i].second;
+      file_options.dllexport_decl = options[i].second;
+    } else if (options[i].first == "safe_boundary_check") {
+      file_options.safe_boundary_check = true;
     } else {
       *error = "Unknown generator option: " + options[i].first;
       return false;
@@ -95,7 +97,7 @@
   string basename = StripProto(file->name());
   basename.append(".pb");
 
-  FileGenerator file_generator(file, dllexport_decl);
+  FileGenerator file_generator(file, file_options);
 
   // Generate header.
   {