Remove the strict-mode flag from store handlers. It's only relevant to the IC stub.

src/ic.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 588 matching lines @@
   // Stub accessors.
   virtual Handle<Code> generic_stub() const {
     if (strict_mode() == kStrictMode) {
       return isolate()->builtins()->StoreIC_Generic_Strict();
     } else {
       return isolate()->builtins()->StoreIC_Generic();
     }
   }
 
   virtual Handle<Code> slow_stub() const {
-    if (strict_mode() == kStrictMode) {
-      return isolate()->builtins()->StoreIC_Slow_Strict();
-    } else {
-      return isolate()->builtins()->StoreIC_Slow();
-    }
+    return isolate()->builtins()->StoreIC_Slow();
   }
 
   virtual Handle<Code> pre_monomorphic_stub() {
     return pre_monomorphic_stub(isolate(), strict_mode());
   }
 
   static Handle<Code> pre_monomorphic_stub(Isolate* isolate,
                                            StrictModeFlag strict_mode) {
     if (strict_mode == kStrictMode) {
       return isolate->builtins()->StoreIC_PreMonomorphic_Strict();
@@ skipping 92 matching lines @@
   }
   static Handle<Code> pre_monomorphic_stub(Isolate* isolate,
                                            StrictModeFlag strict_mode) {
     if (strict_mode == kStrictMode) {
       return isolate->builtins()->KeyedStoreIC_PreMonomorphic_Strict();
     } else {
       return isolate->builtins()->KeyedStoreIC_PreMonomorphic();
     }
   }
   virtual Handle<Code> slow_stub() const {
-    if (strict_mode() == kStrictMode) {
-      return isolate()->builtins()->KeyedStoreIC_Slow_Strict();
-    } else {
-      return isolate()->builtins()->KeyedStoreIC_Slow();
-    }
+    return isolate()->builtins()->KeyedStoreIC_Slow();
   }
   virtual Handle<Code> megamorphic_stub() {
     if (strict_mode() == kStrictMode) {
       return isolate()->builtins()->KeyedStoreIC_Generic_Strict();
     } else {
       return isolate()->builtins()->KeyedStoreIC_Generic();
     }
   }
 
   Handle<Code> StoreElementStub(Handle<JSObject> receiver,
@@ skipping 170 matching lines @@
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedCallIC_MissFromStubFailure);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ElementsTransitionAndStoreIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, BinaryOpIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, CompareNilIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ToBooleanIC_Miss);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_