Remove prototype checks for leaf maps in optimized code.

src/mips/lithium-codegen-mips.h

Index: src/mips/lithium-codegen-mips.h
diff --git a/src/mips/lithium-codegen-mips.h b/src/mips/lithium-codegen-mips.h
index 83bda9a01d8a1eac90be4703ba63da99d37b744a..87c20e59a482a104257474cb354f1c3b707a8564 100644
--- a/src/mips/lithium-codegen-mips.h
+++ b/src/mips/lithium-codegen-mips.h
@@ -54,6 +54,7 @@ class LCodeGen BASE_EMBEDDED {
         deoptimizations_(4, info->zone()),
         deopt_jump_table_(4, info->zone()),
         deoptimization_literals_(8, info->zone()),
+        prototype_maps_(0, info->zone()),
         inlined_function_count_(0),
         scope_(info->scope()),
         status_(UNUSED),
@@ -409,6 +410,7 @@ class LCodeGen BASE_EMBEDDED {
   ZoneList<LEnvironment*> deoptimizations_;
   ZoneList<JumpTableEntry> deopt_jump_table_;
   ZoneList<Handle<Object> > deoptimization_literals_;
+  ZoneList<Handle<Map> > prototype_maps_;
   int inlined_function_count_;
   Scope* const scope_;
   Status status_;