[log] Show branches in BranchesPanel instead of all refs.

This improves performance of sorting references when there are
many tags in the repository.

Better grouping capabilities will be provided later.

platform/vcs-log/impl/src/com/intellij/vcs/log/data/RefsModel.java

@@ -1,5 +1,7 @@
 package com.intellij.vcs.log.data;
 
+import com.intellij.openapi.util.Condition;
+import com.intellij.util.containers.ContainerUtil;
 import com.intellij.vcs.log.Hash;
 import com.intellij.vcs.log.VcsRef;
 import org.jetbrains.annotations.NotNull;
@@ -12,11 +14,19 @@ import java.util.*;
 public class RefsModel {
 
   @NotNull private final Collection<VcsRef> myRefs;
+  @NotNull private final Collection<VcsRef> myBranches;
   @NotNull private final Set<Hash> myRefHashes;
 
   public RefsModel(@NotNull Collection<VcsRef> allRefs) {
     myRefs = allRefs;
 
+    myBranches = ContainerUtil.filter(myRefs, new Condition<VcsRef>() {
+      @Override
+      public boolean value(VcsRef ref) {
+        return ref.getType().isBranch();
+      }
+    });
+
     myRefHashes = new HashSet<Hash>();
     for (VcsRef ref : myRefs) {
       myRefHashes.add(ref.getCommitHash());
@@ -50,4 +60,8 @@ public class RefsModel {
     return Collections.unmodifiableCollection(myRefs);
   }
 
+  @NotNull
+  public Collection<VcsRef> getBranches() {
+    return myBranches;
+  }
 }

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/frame/BranchesPanel.java

@@ -82,7 +82,7 @@ public class BranchesPanel extends JPanel {
 
   @NotNull
   private List<VcsRef> getRefsToDisplayOnPanel() {
-    Collection<VcsRef> allRefs = myDataHolder.getDataPack().getRefsModel().getAllRefs();
+    Collection<VcsRef> allRefs = myDataHolder.getDataPack().getRefsModel().getBranches();
 
     List<VcsRef> refsToShow = new ArrayList<VcsRef>();
     for (Map.Entry<VirtualFile, Collection<VcsRef>> entry : groupByRoot(allRefs).entrySet()) {