Reland of Client side display item cache flag

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 122 matching lines @@
 struct SameSizeAsLayoutObject {
     virtual ~SameSizeAsLayoutObject() { } // Allocate vtable pointer.
     void* pointers[6];
 #if ENABLE(ASSERT)
     unsigned m_debugBitfields : 2;
 #endif
     unsigned m_bitfields;
     unsigned m_bitfields2;
     LayoutRect rect; // Stores the previous paint invalidation rect.
     LayoutPoint position; // Stores the previous position from the paint invalidation container.
+    DisplayItemCacheGeneration cacheGeneration;
 };
 
 static_assert(sizeof(LayoutObject) == sizeof(SameSizeAsLayoutObject), "LayoutObject should stay small");
 
 bool LayoutObject::s_affectsParentBlock = false;
 
 typedef HashMap<const LayoutObject*, LayoutRect> SelectionPaintInvalidationMap;
 static SelectionPaintInvalidationMap* selectionPaintInvalidationMap = nullptr;
 
 // The pointer to paint properties is implemented as a global hash map temporarily,
@@ skipping 3533 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif