Ensure text nodes get an object if we're unsure that they will be collapsed

third_party/WebKit/Source/core/dom/Text.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 289 matching lines @@
             return false;
 
         // Avoiding creation of a layoutObject for the text node is a non-essential memory optimization.
         // So to avoid blowing up on very wide DOMs, we limit the number of siblings to visit.
         unsigned maxSiblingsToVisit = 50;
 
         LayoutObject* first = parent.slowFirstChild();
         while (first && first->isFloatingOrOutOfFlowPositioned() && maxSiblingsToVisit--)
             first = first->nextSibling();
         if (!first || first == layoutObject() || LayoutTreeBuilderTraversal::nextSiblingLayoutObject(*this) == first) {
+            // If we're adding children to this flow our previous siblings are not in the layout tree yet so we
+            // cannot know if we will be the first child in the line and collapse away. We have to assume we need a layout object.
+            Node* firstChildNode = parent.node() ? LayoutTreeBuilderTraversal::firstChild(*parent.node()) : nullptr;
+            if (first && first == layoutObject() && firstChildNode && !firstChildNode->layoutObject())
+                return true;
+
             // Whitespace at the start of a block just goes away.  Don't even
             // make a layout object for this text.
-            return false;
+            return !firstChildNode;
         }
     }
     return true;
 }
 
 static bool isSVGText(Text* text)
 {
     Node* parentOrShadowHostNode = text->parentOrShadowHostNode();
     ASSERT(parentOrShadowHostNode);
     return parentOrShadowHostNode->isSVGElement() && !isSVGForeignObjectElement(*parentOrShadowHostNode);
@@ skipping 111 matching lines @@
             result.appendLiteral("; ");
         result.appendLiteral("value=");
         result.append(s);
     }
 
     strncpy(buffer, result.toString().utf8().data(), length - 1);
 }
 #endif
 
 } // namespace blink