(early draft) Strict mode - throw exception on assignment to read only property.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 24887a0efb6adba9fc902b813879b695997b7fb9..478eaad51a786889044dde977f3f2500c1445a25 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -2615,7 +2615,8 @@ Code::Flags Code::ComputeFlags(Kind kind,
   ASSERT(extra_ic_state == kNoExtraICState ||
          (kind == CALL_IC && (ic_state == MONOMORPHIC ||
                               ic_state == MONOMORPHIC_PROTOTYPE_FAILURE)) ||
-         (kind == STORE_IC));
+         (kind == STORE_IC) ||
+         (kind == KEYED_STORE_IC));
   // Compute the bit mask.
   int bits = kind << kFlagsKindShift;
   if (in_loop) bits |= kFlagsICInLoopMask;
@@ -3737,7 +3738,8 @@ MaybeObject* JSObject::SetHiddenPropertiesObject(Object* hidden_obj) {
   ASSERT(!IsJSGlobalProxy());
   return SetPropertyPostInterceptor(Heap::hidden_symbol(),
                                     hidden_obj,
-                                    DONT_ENUM);
+                                    DONT_ENUM,
+                                    kNonStrictMode);
 }