Remove the remaining parts of ignorePendingStylesheets and placeholder styles.

sky/engine/core/dom/RenderTreeBuilder.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 30 matching lines @@
     STACK_ALLOCATED();
 public:
     RenderTreeBuilder(Node* node, RenderStyle* style)
         : m_node(node)
         , m_renderingParent(nullptr)
         , m_style(style)
     {
         ASSERT(!node->renderer());
         ASSERT(node->needsAttach());
         ASSERT(node->document().inStyleRecalc());
-
-        // FIXME: We should be able to ASSERT(node->inActiveDocument()) but childrenChanged is called
-        // before ChildNodeInsertionNotifier in ContainerNode's methods and some implementations
-        // will trigger a layout inside childrenChanged.
-        // Mainly HTMLTextAreaElement::childrenChanged calls HTMLTextFormControlElement::setSelectionRange
-        // which does an updateLayoutIgnorePendingStylesheets.
+        ASSERT(node->inActiveDocument());
 
         m_renderingParent = NodeRenderingTraversal::parent(node, &m_parentDetails);
     }
 
     void createRendererForTextIfNeeded();
     void createRendererForElementIfNeeded();
 
 private:
     RenderObject* parentRenderer() const;
     RenderObject* nextRenderer() const;
     bool shouldCreateRenderer() const;
     RenderStyle& style() const;
 
     RawPtr<Node> m_node;
     RawPtr<ContainerNode> m_renderingParent;
     NodeRenderingTraversal::ParentDetails m_parentDetails;
     mutable RefPtr<RenderStyle> m_style;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_DOM_RENDERTREEBUILDER_H_