third_party/protobuf: update to upstream r371

third_party/protobuf/src/google/protobuf/extension_set.cc

Index: third_party/protobuf/src/google/protobuf/extension_set.cc
diff --git a/third_party/protobuf/src/google/protobuf/extension_set.cc b/third_party/protobuf/src/google/protobuf/extension_set.cc
index c1b59e868568bdb3c943483ca96a06ee5deecac6..dbb091597d69eb2e458c926bc6e5f033d680ad07 100644
--- a/third_party/protobuf/src/google/protobuf/extension_set.cc
+++ b/third_party/protobuf/src/google/protobuf/extension_set.cc
@@ -186,6 +186,18 @@ int ExtensionSet::ExtensionSize(int number) const {
   return iter->second.GetSize();
 }
 
+FieldType ExtensionSet::ExtensionType(int number) const {
+  map<int, Extension>::const_iterator iter = extensions_.find(number);
+  if (iter == extensions_.end()) {
+    GOOGLE_LOG(DFATAL) << "Don't lookup extension types if they aren't present (1). ";
+    return 0;
+  }
+  if (iter->second.is_cleared) {
+    GOOGLE_LOG(DFATAL) << "Don't lookup extension types if they aren't present (2). ";
+  }
+  return iter->second.type;
+}
+
 void ExtensionSet::ClearExtension(int number) {
   map<int, Extension>::iterator iter = extensions_.find(number);
   if (iter == extensions_.end()) return;