*** NOT FOR LANDING *** Paint investigations for bug 667370

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1434 matching lines @@
   CHECK(!firstChild || firstChild->isBox());
   LayoutBox* next = toLayoutBox(firstChild);
   LayoutBox* lastNormalFlowChild = nullptr;
 
   while (next) {
     LayoutBox* child = next;
     LayoutObject* nextSibling = child->nextSibling();
     CHECK(!nextSibling || nextSibling->isBox());
     next = toLayoutBox(nextSibling);
 
-    child->setMayNeedPaintInvalidation();
+//    child->setMayNeedPaintInvalidation();
 
     if (childToExclude == child)
       continue;  // Skip this child, since it will be positioned by the
                  // specialized subclass (fieldsets and ruby runs).
 
     updateBlockChildDirtyBitsBeforeLayout(relayoutChildren, *child);
 
     if (child->isOutOfFlowPositioned()) {
       child->containingBlock()->insertPositionedObject(child);
       adjustPositionedBlock(*child, layoutInfo);
@@ skipping 3139 matching lines @@
   return LayoutBlock::invalidatePaintIfNeeded(paintInvalidationState);
 }
 
 void LayoutBlockFlow::invalidateDisplayItemClients(
     PaintInvalidationReason invalidationReason) const {
   BlockFlowPaintInvalidator(*this).invalidateDisplayItemClients(
       invalidationReason);
 }
 
 }  // namespace blink