Simplify computation of the invalidation rect for a frame.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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 297 matching lines @@
 {
     Widget* widget = this->widget();
     ASSERT(widget);
 
     LayoutRect contentBox = contentBoxRect();
     LayoutRect absoluteContentBox(localToAbsoluteQuad(FloatQuad(FloatRect(contentBox))).boundingBox());
     if (widget->isFrameView()) {
         contentBox.setLocation(absoluteContentBox.location());
         return setWidgetGeometry(contentBox);
     }
-
+    // TODO(chrishtr): why are these widgets using an absolute rect for their frameRect?
     return setWidgetGeometry(absoluteContentBox);
 }
 
 // Widgets are always placed on integer boundaries, so rounding the size is actually
 // the desired behavior. This function is here because it's otherwise seldom what we
 // want to do with a LayoutRect.
 static inline IntRect roundedIntRect(const LayoutRect& rect)
 {
     return IntRect(roundedIntPoint(rect.location()), roundedIntSize(rect.size()));
 }
@@ skipping 30 matching lines @@
 
 bool LayoutPart::isThrottledFrameView() const
 {
     if (!widget() || !widget()->isFrameView())
         return false;
     const FrameView* frameView = toFrameView(widget());
     return frameView->shouldThrottleRendering();
 }
 
 }