Fix CC root visiting bug

Also some cleanup.

Change-Id: Ia3de8f2d409770be3619ec116e8b06ecd82338fe
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 33d75d2..12fa546 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -914,7 +914,8 @@
 void ClassLinker::VisitClassRoots(RootVisitor* visitor, VisitRootFlags flags) {
   WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
   if ((flags & kVisitRootFlagAllRoots) != 0) {
-    BufferedRootVisitor<128> buffered_visitor(visitor, RootInfo(kRootStickyClass));
+    BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(
+        visitor, RootInfo(kRootStickyClass));
     for (GcRoot<mirror::Class>& root : class_table_) {
       buffered_visitor.VisitRoot(root);
     }