Mark more roots.

This is most of the stuff. (Everything that currently exists, though there's
more to come.)

Change-Id: I235a21b006820a027c494374a5b52ffefed89c32
diff --git a/src/reference_table.h b/src/reference_table.h
index 13317ea..9142b7c 100644
--- a/src/reference_table.h
+++ b/src/reference_table.h
@@ -22,6 +22,8 @@
 #include <string>
 #include <vector>
 
+#include "heap.h"
+
 namespace art {
 
 class Object;
@@ -43,12 +45,15 @@
 
   void Dump() const;
 
+  void VisitRoots(Heap::RootVisitor* visitor, void* arg);
+
  private:
-  static void Dump(const std::vector<const Object*>& entries);
+  typedef std::vector<const Object*> Table;
+  static void Dump(const Table& entries);
   friend class IndirectReferenceTable; // For Dump.
 
   std::string name_;
-  std::vector<const Object*> entries_;
+  Table entries_;
   size_t max_size_;
 };