Helium: Initial proto and Syncable interface definition

blimp/net/helium/vector_clock.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "blimp/net/helium/vector_clock.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 
@@ skipping 36 matching lines @@
 VectorClock VectorClock::MergeWith(const VectorClock& other) const {
   VectorClock result(std::max(local_revision_, other.local_revision()),
                      std::max(remote_revision_, other.remote_revision()));
   return result;
 }
 
 void VectorClock::IncrementLocal() {
   local_revision_++;
 }
 
+proto::VectorClockMessage VectorClock::ToProto() const {
+  proto::VectorClockMessage result;
+  result.set_local_revision(local_revision_);
+  result.set_remote_revision(remote_revision_);
+  return result;
+}
+
+VectorClock VectorClock::Invert() const {
+  VectorClock result;

[steimel, 2016/10/06 17:44:33]

Would it make more sense to use the other constructor here? i.e. have a 1-liner
function:

return VectorClock(remote_revision_, local_revision_);

[scf, 2016/10/06 19:47:17]

good catch

+  result.set_local_revision(remote_revision_);
+  result.set_remote_revision(local_revision_);
+  return result;
+}
+
 }  // namespace blimp