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/mark_sweep.h b/src/mark_sweep.h
index 047e357..f20cc41 100644
--- a/src/mark_sweep.h
+++ b/src/mark_sweep.h
@@ -127,6 +127,8 @@
                          Object** phantom_references);
 
   void SweepSystemWeaks();
+  void SweepMonitorList();
+  void SweepJniWeakGlobals();
 
   MarkStack* mark_stack_;
 
@@ -148,6 +150,8 @@
 
   Object* cleared_reference_list_;
 
+  friend class InternTableEntryIsUnmarked;
+
   DISALLOW_COPY_AND_ASSIGN(MarkSweep);
 };