Don't expand empty rect during rect mapping

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 2310 matching lines @@
   if (filterSkipped)
     inflateVisualRectForFilterUnderContainer(rect, *container, ancestor);
 
   // We are now in our parent container's coordinate space. Apply our transform
   // to obtain a bounding box in the parent's coordinate space that encloses us.
   if (hasLayer() && layer()->transform()) {
     // Use enclosingIntRect because we cannot properly compute pixel snapping
     // for painted elements within the transform since we don't know the desired
     // subpixel accumulation at this point, and the transform may include a
     // scale.
-    rect = LayoutRect(layer()->transform()->mapRect(enclosingIntRect(rect)));
+    FloatRect floatRect =
+        rect.isEmpty() ? FloatRect(rect) : FloatRect(enclosingIntRect(rect));
+    rect = LayoutRect(layer()->transform()->mapRect(floatRect));
   }
   LayoutPoint topLeft = rect.location();
   if (container->isBox()) {
     topLeft.moveBy(topLeftLocation(toLayoutBox(container)));
     // If the row is the ancestor, however, add its offset back in. In effect,
     // this passes from the joint <td> / <tr> coordinate space to the parent
     // space, then back to <tr> / <td>.
     if (tableRowContainer)
       topLeft.moveBy(
           -tableRowContainer->topLeftLocation(toLayoutBox(container)));
@@ skipping 3233 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink