Fix paint invalidation rect tracking within composited scrolling layers.

Source/core/paint/DeprecatedPaintLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 309 matching lines @@
 
 void DeprecatedPaintLayer::updateLayerPositionsAfterScrollRecursive(const DoubleSize& scrollDelta, bool paintInvalidationContainerWasScrolled)
 {
     updateLayerPosition();
     if (paintInvalidationContainerWasScrolled && !isPaintInvalidationContainer()) {
         // Paint invalidation rects are in the coordinate space of the paint invalidation container.
         // If it has scrolled, the rect must be adjusted. Note that it is not safe to reset it to
         // the current bounds rect, as the LayoutObject may have moved since the last invalidation.
         // FIXME(416535): Ideally, pending invalidations of scrolling content should be stored in
         // the coordinate space of the scrolling content layer, so that they need no adjustment.
-        LayoutRect invalidationRect = m_layoutObject->previousPaintInvalidationRect();
-        invalidationRect.move(LayoutSize(scrollDelta));
-        m_layoutObject->setPreviousPaintInvalidationRect(invalidationRect);
+        m_layoutObject->adjustPreviousPaintInvalidationForScrollIfNeeded(scrollDelta);
     }
     for (DeprecatedPaintLayer* child = firstChild(); child; child = child->nextSibling()) {
         child->updateLayerPositionsAfterScrollRecursive(scrollDelta,
             paintInvalidationContainerWasScrolled && !child->isPaintInvalidationContainer());
     }
 }
 
 void DeprecatedPaintLayer::updateTransformationMatrix()
 {
     if (m_transform) {
@@ skipping 2317 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif