Refactor CommitSoyData to use more of a builder pattern

These are created one-off on every request thread, so making them
mutable is safe enough, and it allows us to get rid of the messy
constructors. Be more explicit about which keys require which optional
arguments.

Change-Id: Ic175369898c206278bd8bc862bef0744b27ee79a

gitiles-servlet/src/main/java/com/google/gitiles/LogSoyData.java

diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/LogSoyData.java b/gitiles-servlet/src/main/java/com/google/gitiles/LogSoyData.java
index 77bd36a..f4be0a4 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/LogSoyData.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/LogSoyData.java
@@ -18,29 +18,23 @@
 import com.google.common.collect.Maps;
 import com.google.gitiles.CommitSoyData.KeySet;
 
-import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.ObjectId;
-import org.eclipse.jgit.lib.Ref;
-import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 import javax.annotation.Nullable;
 import javax.servlet.http.HttpServletRequest;
 
 public class LogSoyData {
   private final HttpServletRequest req;
-  private final Repository repo;
   private final GitilesView view;
 
-  public LogSoyData(HttpServletRequest req, Repository repo, GitilesView view) {
+  public LogSoyData(HttpServletRequest req, GitilesView view) {
     this.req = req;
-    this.repo = repo;
     this.view = view;
   }
 
@@ -49,11 +43,9 @@
     Map<String, Object> data = Maps.newHashMapWithExpectedSize(3);
 
     Paginator paginator = new Paginator(walk, limit, start);
-    Map<AnyObjectId, Set<Ref>> refsById = repo.getAllRefsByPeeledObjectId();
     List<Map<String, Object>> entries = Lists.newArrayListWithCapacity(limit);
     for (RevCommit c : paginator) {
-      entries.add(new CommitSoyData(null, req, repo, walk, view, refsById)
-          .toSoyData(c, KeySet.SHORTLOG));
+      entries.add(new CommitSoyData().toSoyData(req, c, KeySet.SHORTLOG));
     }
 
     data.put("entries", entries);