Fix under-invalidation about view background change caused by body style change

Source/core/layout/LayoutView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 147 matching lines @@
     // and discrete paint invalidation rects, so marking full paint invalidation here is more likely to cost less.
     // Otherwise, per-descendant paint invalidation is more likely to avoid unnecessary full paint invalidation.
 
     if (shouldUsePrintingLayout())
         return true;
 
     if (!style()->isHorizontalWritingMode() || size().width() != viewWidth())
         return true;
 
     if (size().height() != viewHeight()) {
-        if (LayoutObject* backgroundRenderer = this->backgroundRenderer()) {
+        if (LayoutObject* backgroundLayoutObject = this->backgroundLayoutObject()) {
             // When background-attachment is 'fixed', we treat the viewport (instead of the 'root'
             // i.e. html or body) as the background positioning area, and we should full paint invalidation
             // viewport resize if the background image is not composited and needs full paint invalidation on
             // background positioning area resize.
             if (!m_compositor || !m_compositor->needsFixedRootBackgroundLayer(layer())) {
-                if (backgroundRenderer->style()->hasFixedBackgroundImage()
-                    && mustInvalidateFillLayersPaintOnHeightChange(backgroundRenderer->style()->backgroundLayers()))
+                if (backgroundLayoutObject->style()->hasFixedBackgroundImage()
+                    && mustInvalidateFillLayersPaintOnHeightChange(backgroundLayoutObject->style()->backgroundLayers()))
                     return true;
             }
         }
     }
 
     return false;
 }
 
 void LayoutView::layout()
 {
@@ skipping 619 matching lines @@
 
 IntRect LayoutView::unscaledDocumentRect() const
 {
     LayoutRect overflowRect(layoutOverflowRect());
     flipForWritingMode(overflowRect);
     return pixelSnappedIntRect(overflowRect);
 }
 
 bool LayoutView::rootBackgroundIsEntirelyFixed() const
 {
-    if (LayoutObject* backgroundRenderer = this->backgroundRenderer())
-        return backgroundRenderer->hasEntirelyFixedBackground();
+    if (LayoutObject* backgroundLayoutObject = this->backgroundLayoutObject())
+        return backgroundLayoutObject->hasEntirelyFixedBackground();
     return false;
 }
 
-LayoutObject* LayoutView::backgroundRenderer() const
+LayoutObject* LayoutView::backgroundLayoutObject() const
 {
     if (Element* documentElement = document().documentElement()) {
         if (LayoutObject* rootObject = documentElement->layoutObject())
             return rootObject->layoutObjectForRootBackground();
     }
     return 0;
 }
 
-LayoutRect LayoutView::backgroundRect(LayoutBox* backgroundRenderer) const
+LayoutRect LayoutView::backgroundRect(LayoutBox* backgroundLayoutObject) const
 {
     if (!hasColumns())
         return LayoutRect(unscaledDocumentRect());
 
     ColumnInfo* columnInfo = this->columnInfo();
     LayoutRect backgroundRect(0, 0, columnInfo->desiredColumnWidth(), columnInfo->columnHeight() * columnInfo->columnCount());
     if (!isHorizontalWritingMode())
         backgroundRect = backgroundRect.transposedRect();
-    backgroundRenderer->flipForWritingMode(backgroundRect);
+    backgroundLayoutObject->flipForWritingMode(backgroundRect);
 
     return backgroundRect;
 }
 
 IntRect LayoutView::documentRect() const
 {
     FloatRect overflowRect(unscaledDocumentRect());
     if (hasTransformRelatedProperty())
         overflowRect = layer()->currentTransform().mapRect(overflowRect);
     return IntRect(overflowRect);
@@ skipping 94 matching lines @@
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 void LayoutView::willBeDestroyed()
 {
     LayoutBlockFlow::willBeDestroyed();
     m_compositor.clear();
 }
 
 } // namespace blink