Rename "paint invalidation rect" etc. to "visual rect".

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 812 matching lines @@
   // collapsing now.
   child.computeAndSetBlockDirectionMargins(this);
 
   // Try to guess our correct logical top position. In most cases this guess
   // will be correct. Only if we're wrong (when we compute the real logical top
   // position) will we have to potentially relayout.
   LayoutUnit estimateWithoutPagination;
   LayoutUnit logicalTopEstimate =
       estimateLogicalTopPosition(child, layoutInfo, estimateWithoutPagination);
 
-  // Cache our old rect so that we can dirty the proper paint invalidation rects
-  // if the child moves.
   LayoutRect oldRect = child.frameRect();
 
   if (LayoutFlowThread* flowThread = flowThreadContainingBlock())
     layoutInfo.storeMultiColumnLayoutState(*flowThread);
 
   // Use the estimated block position and lay out the child if needed. After
   // child layout, when we have enough information to perform proper margin
   // collapsing, float clearing and pagination, we may have to reposition and
   // lay out again if the estimate was wrong.
   bool childNeededLayout =
@@ skipping 3707 matching lines @@
   return LayoutBlock::invalidatePaintIfNeeded(paintInvalidationState);
 }
 
 void LayoutBlockFlow::invalidateDisplayItemClients(
     PaintInvalidationReason invalidationReason) const {
   BlockFlowPaintInvalidator(*this).invalidateDisplayItemClients(
       invalidationReason);
 }
 
 }  // namespace blink