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 e0779725be961017c5d5d640b65adc646799f692..3de3244997ebc19f5b29493d5a6945f9a09a84bc 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),
@@ -408,6 +409,7 @@ 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_;