Check CallSite arguments more rigorously

src/messages.cc

Index: src/messages.cc
diff --git a/src/messages.cc b/src/messages.cc
index 2062917e457a08a1baac6d1ea648bb3fb90cbfad..7228ba215110a0fd87bcb817419f35dd2ef2334b 100644
--- a/src/messages.cc
+++ b/src/messages.cc
@@ -182,14 +182,9 @@ CallSite::CallSite(Isolate* isolate, Handle<JSObject> call_site_obj)
       // invalid: neither javascript nor wasm
       return;
     }
-    Handle<Object> maybe_wasm_obj = JSObject::GetDataProperty(
-        call_site_obj, isolate->factory()->call_site_wasm_obj_symbol());
-    if (!maybe_wasm_obj->IsJSObject()) {
-      // invalid: neither javascript nor wasm
-      return;
-    }
     // wasm
-    wasm_obj_ = Handle<JSObject>::cast(maybe_wasm_obj);
+    wasm_obj_ = Handle<JSObject>::cast(JSObject::GetDataProperty(
+        call_site_obj, isolate->factory()->call_site_wasm_obj_symbol()));
     wasm_func_index_ = Smi::cast(*maybe_wasm_func_index)->value();
     DCHECK(static_cast<int>(wasm_func_index_) >= 0);
   }
@@ -210,8 +205,8 @@ Handle<Object> CallSite::GetFileName() {
 
 Handle<Object> CallSite::GetFunctionName() {
   if (IsWasm()) {
-    MaybeHandle<String> name = wasm::GetWasmFunctionName(
-        Handle<JSObject>::cast(wasm_obj_), wasm_func_index_);
+    MaybeHandle<String> name =
+        wasm::GetWasmFunctionName(wasm_obj_, wasm_func_index_);
     if (name.is_null()) return isolate_->factory()->null_value();
     return name.ToHandleChecked();
   }