Add ChangeMessagesUtil to assist with notedb migration

Like ApprovalsUtil, we added an abstraction layer to assist in the
migration to notedb. This utility class helps to write to either the
notedb or the reviewdb depending on the state of the NotesMigration
instance. Additionally, in this change, I modified all callers of
ChangeMessageAccess (which uses the ReviewDb) to instead use
ChangeMessagesUtil.

Change-Id: Id007ed8e01bd1318f70d804124e1f482a77234fd

gerrit-server/src/main/java/com/google/gerrit/server/change/PutTopic.java

@@ -25,10 +25,12 @@ import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.ChangeMessage;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.change.PutTopic.Input;
 import com.google.gerrit.server.index.ChangeIndexer;
+import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.util.TimeUtil;
 import com.google.gwtorm.server.AtomicUpdate;
@@ -38,7 +40,6 @@ import com.google.inject.Provider;
 import com.google.inject.Singleton;
 
 import java.io.IOException;
-import java.util.Collections;
 
 @Singleton
 class PutTopic implements RestModifyView<ChangeResource, Input>,
@@ -46,6 +47,8 @@ class PutTopic implements RestModifyView<ChangeResource, Input>,
   private final Provider<ReviewDb> dbProvider;
   private final ChangeIndexer indexer;
   private final ChangeHooks hooks;
+  private final ChangeUpdate.Factory updateFactory;
+  private final ChangeMessagesUtil cmUtil;
 
   static class Input {
     @DefaultInput
@@ -54,10 +57,13 @@ class PutTopic implements RestModifyView<ChangeResource, Input>,
 
   @Inject
   PutTopic(Provider<ReviewDb> dbProvider, ChangeIndexer indexer,
-      ChangeHooks hooks) {
+      ChangeHooks hooks, ChangeUpdate.Factory updateFactory,
+      ChangeMessagesUtil cmUtil) {
     this.dbProvider = dbProvider;
     this.indexer = indexer;
     this.hooks = hooks;
+    this.updateFactory = updateFactory;
+    this.cmUtil = cmUtil;
   }
 
   @Override
@@ -94,6 +100,7 @@ class PutTopic implements RestModifyView<ChangeResource, Input>,
           currentUser.getAccountId(), TimeUtil.nowTs(),
           change.currentPatchSetId());
       cmsg.setMessage(summary);
+      ChangeUpdate update;
 
       db.changes().beginTransaction(change.getId());
       try {
@@ -106,11 +113,16 @@ class PutTopic implements RestModifyView<ChangeResource, Input>,
               return change;
             }
           });
-        db.changeMessages().insert(Collections.singleton(cmsg));
+
+        //TODO(yyonas): atomic update was not propagated
+        update = updateFactory.create(control);
+        cmUtil.addChangeMessage(db, update, cmsg);
+
         db.commit();
       } finally {
         db.rollback();
       }
+      update.commit();
       CheckedFuture<?, IOException> indexFuture =
           indexer.indexAsync(change.getId());
       hooks.doTopicChangedHook(change, currentUser.getAccount(),