Revert of Remove obsolete code that invalidates document element on LayoutView resize (patchset #3 …

third_party/WebKit/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.
  *
@@ skipping 229 matching lines @@
       m_fragmentationContext = wrapUnique(new ViewFragmentationContext(*this));
       m_paginationStateChanged = true;
     }
   } else if (m_fragmentationContext) {
     m_fragmentationContext.reset();
     m_paginationStateChanged = true;
   }
 
   SubtreeLayoutScope layoutScope(*this);
 
+  LayoutRect oldLayoutOverflowRect = layoutOverflowRect();
+
   // Use calcWidth/Height to get the new width/height, since this will take the
   // full page zoom factor into account.
   bool relayoutChildren =
       !shouldUsePrintingLayout() &&
       (!m_frameView || logicalWidth() != viewLogicalWidthForBoxSizing() ||
        logicalHeight() != viewLogicalHeightForBoxSizing());
   if (relayoutChildren) {
     layoutScope.setChildNeedsLayout(this);
     for (LayoutObject* child = firstChild(); child;
          child = child->nextSibling()) {
@@ skipping 14 matching lines @@
   }
 
   ASSERT(!m_layoutState);
   if (!needsLayout())
     return;
 
   LayoutState rootLayoutState(pageLogicalHeight(), *this);
 
   layoutContent();
 
+  if (layoutOverflowRect() != oldLayoutOverflowRect) {
+    // The document element paints the viewport background, so we need to
+    // invalidate it when layout overflow changes.
+    // FIXME: Improve viewport background styling/invalidation/painting.
+    // crbug.com/475115
+    if (Element* documentElement = document().documentElement()) {
+      if (LayoutObject* rootObject = documentElement->layoutObject())
+        rootObject->setShouldDoFullPaintInvalidation();
+    }
+  }
+
 #if ENABLE(ASSERT)
   checkLayoutState();
 #endif
   clearNeedsLayout();
 }
 
 LayoutRect LayoutView::visualOverflowRect() const {
   // In root layer scrolling mode, the LayoutView performs overflow clipping
   // like a regular scrollable div.
   if (RuntimeEnabledFeatures::rootLayerScrollingEnabled())
@@ skipping 746 matching lines @@
   if (block)
     block->adjustChildDebugRect(rect);
 
   rect.setWidth(LayoutUnit(viewWidth(IncludeScrollbars)));
   rect.setHeight(LayoutUnit(viewHeight(IncludeScrollbars)));
 
   return rect;
 }
 
 }  // namespace blink