[debugger] use object with null proto to materialize scopes.

Otherwise property lookups would also travel up the prototype chain, which makes no sense for the debugger use case.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1928463002

Cr-Commit-Position: refs/heads/master@{#35806}

src/debug/debug-scopes.cc

@@ -453,7 +453,7 @@ MaybeHandle<JSObject> ScopeIterator::MaterializeScriptScope() {
       global->native_context()->script_context_table());
 
   Handle<JSObject> script_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
 
   for (int context_index = 0; context_index < script_contexts->used();
        context_index++) {
@@ -470,7 +470,7 @@ MaybeHandle<JSObject> ScopeIterator::MaterializeLocalScope() {
   Handle<JSFunction> function = GetFunction();
 
   Handle<JSObject> local_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
   frame_inspector_->MaterializeStackLocals(local_scope, function);
 
   Handle<Context> frame_context =
@@ -513,7 +513,7 @@ Handle<JSObject> ScopeIterator::MaterializeClosure() {
   // Allocate and initialize a JSObject with all the content of this function
   // closure.
   Handle<JSObject> closure_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
 
   // Fill all context locals to the context extension.
   CopyContextLocalsToScopeObject(scope_info, context, closure_scope);
@@ -540,7 +540,7 @@ Handle<JSObject> ScopeIterator::MaterializeCatchScope() {
   Handle<Object> thrown_object(context->get(Context::THROWN_OBJECT_INDEX),
                                isolate_);
   Handle<JSObject> catch_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
   JSObject::SetOwnPropertyIgnoreAttributes(catch_scope, name, thrown_object,
                                            NONE)
       .Check();
@@ -562,7 +562,7 @@ Handle<JSObject> ScopeIterator::WithContextExtension() {
 // block context.
 Handle<JSObject> ScopeIterator::MaterializeBlockScope() {
   Handle<JSObject> block_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
 
   Handle<Context> context = Handle<Context>::null();
   if (!nested_scope_chain_.is_empty()) {
@@ -599,7 +599,7 @@ MaybeHandle<JSObject> ScopeIterator::MaterializeModuleScope() {
   // Allocate and initialize a JSObject with all the members of the debugged
   // module.
   Handle<JSObject> module_scope =
-      isolate_->factory()->NewJSObject(isolate_->object_function());
+      isolate_->factory()->NewJSObjectWithNullProto();
 
   // Fill all context locals.
   CopyContextLocalsToScopeObject(scope_info, context, module_scope);

src/runtime/runtime-debug.cc

@@ -1294,10 +1294,7 @@ RUNTIME_FUNCTION(Runtime_DebugGetLoadedScripts) {
   }
 
   // Return result as a JS array.
-  Handle<JSObject> result =
-      isolate->factory()->NewJSObject(isolate->array_function());
-  JSArray::SetContent(Handle<JSArray>::cast(result), instances);
-  return *result;
+  return *isolate->factory()->NewJSArrayWithElements(instances);
 }
 
 static bool HasInPrototypeChainIgnoringProxies(Isolate* isolate,