Mark when we may have been invalidated to early out on repaintTreeAfterLayout.

Source/core/rendering/RenderBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 344 matching lines @@
     Vector<ImageResource*> images;
     appendImagesFromStyle(images, *newStyle);
     if (images.isEmpty())
         ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->removeRenderObject(this);
     else
         ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->addRenderObject(this);
 }
 
 void RenderBlock::repaintTreeAfterLayout()
 {
+    bool maybeInvalidated = mayNeedInvalidation();
     RenderBox::repaintTreeAfterLayout();
 
+    if (!maybeInvalidated)
+        return;
+
     // Take care of positioned objects. This is required as LayoutState keeps a single clip rect.
     if (TrackedRendererListHashSet* positionedObjects = this->positionedObjects()) {
         TrackedRendererListHashSet::iterator end = positionedObjects->end();
         LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
         for (TrackedRendererListHashSet::iterator it = positionedObjects->begin(); it != end; ++it)
             (*it)->repaintTreeAfterLayout();
     }
 }
 
 RenderBlock* RenderBlock::continuationBefore(RenderObject* beforeChild)
@@ skipping 1241 matching lines @@
     if (hasColumns())
         view()->layoutState()->clearPaginationInformation(); // Positioned objects are not part of the column flow, so they don't paginate with the columns.
 
     RenderBox* r;
     TrackedRendererListHashSet::iterator end = positionedDescendants->end();
     for (TrackedRendererListHashSet::iterator it = positionedDescendants->begin(); it != end; ++it) {
         r = *it;
 
         // FIXME: this should only be set from clearNeedsLayout crbug.com/361250
         r->setLayoutDidGetCalled(true);
+        r->setMayNeedInvalidation(true);
 
         SubtreeLayoutScope layoutScope(*r);
         // A fixed position element with an absolute positioned ancestor has no way of knowing if the latter has changed position. So
         // if this is a fixed position element, mark it for layout if it has an abspos ancestor and needs to move with that ancestor, i.e.
         // it has static position.
         markFixedPositionObjectForLayoutIfNeeded(r, layoutScope);
         if (info == LayoutOnlyFixedPositionedObjects) {
             r->layoutIfNeeded();
             continue;
         }
@@ skipping 3335 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace WebCore