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

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index d718c8875b5973e11a6cc6151f96bb773f4baa55..a2d0827dc7bf3ac6d54c166fd39e14f76a3b1042 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2286,7 +2286,8 @@ bool v8::Object::Set(v8::Handle<Value> key, v8::Handle<Value> value,
       self,
       key_obj,
       value_obj,
-      static_cast<PropertyAttributes>(attribs));
+      static_cast<PropertyAttributes>(attribs),
+      i::kNonStrictMode);  // TODO(mmaly): v8::Object::Set API. Needs strict?
   has_pending_exception = obj.is_null();
   EXCEPTION_BAILOUT_CHECK(false);
   return true;
@@ -2711,7 +2712,8 @@ bool v8::Object::SetHiddenValue(v8::Handle<v8::String> key,
       hidden_props,
       key_obj,
       value_obj,
-      static_cast<PropertyAttributes>(None));
+      static_cast<PropertyAttributes>(None),
+      i::kNonStrictMode);  // v8::Object::SetHiddenValue doesn't need strict.
   has_pending_exception = obj.is_null();
   EXCEPTION_BAILOUT_CHECK(false);
   return true;