Use weak cells in map checks in polymorphic ICs.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
index 383233bd25146f9c7ca910964ccab87a94404cde..158f1b18dba81d62287014ca4b9c1c08d1a3afc9 100644
--- a/src/ia32/macro-assembler-ia32.h
+++ b/src/ia32/macro-assembler-ia32.h
@@ -299,6 +299,13 @@ class MacroAssembler: public Assembler {
     }
   }
 
+  // Compare the given value and the value of weak cell.
+  void CmpWeakValue(Register value, Handle<WeakCell> cell, Register scratch);
+
+  // Load the value of the weak cell in the value register. Branch to the given
+  // miss label if the weak cell was cleared.
+  void LoadWeakValue(Register value, Handle<WeakCell> cell, Label* miss);
+
   // ---------------------------------------------------------------------------
   // JavaScript invokes