Remove the old multicol implementation.

Source/core/paint/BoxPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/BoxPainter.h"
 
 #include "core/HTMLNames.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLFrameOwnerElement.h"
@@ skipping 56 matching lines @@
 
     // Use the visual overflow rect here, because it will include overflow introduced by the theme.
     LayoutRect bounds = m_layoutBox.visualOverflowRect();
     bounds.moveBy(paintOffset);
     return LayoutRect(pixelSnappedIntRect(bounds));
 }
 
 LayoutRect BoxPainter::rootBackgroundRect()
 {
     LayoutView* layoutView = m_layoutBox.view();
-    LayoutRect result = layoutView->backgroundRect(&m_layoutBox);
+    LayoutRect result(layoutView->unscaledDocumentRect());

[dsinclair, 2015/06/03 13:52:58]

This change seems unrelated?

[mstensho (USE GERRIT), 2015/06/03 13:56:21]

I killed LayoutView::backgroundRect(), because it no longer did anything unique,
because of the removal of the old multicol code. Should I put it back?

[mstensho (USE GERRIT), 2015/06/03 14:05:52]

Done.

     // In root-layer-scrolls mode, root background is painted in coordinates of the
     // root scrolling contents layer, so don't need scroll offset adjustment.
     if (layoutView->hasOverflowClip() && !layoutView->frame()->settings()->rootLayerScrolls())
         result.move(-layoutView->scrolledContentOffset());
     return result;
 }
 
 namespace {
 
 bool bleedAvoidanceIsClipping(BackgroundBleedAvoidance bleedAvoidance)
@@ skipping 1035 matching lines @@
                 else
                     clippedEdges |= GraphicsContext::BottomEdge;
             }
             // TODO: support non-integer shadows - crbug.com/334828
             context->drawInnerShadow(border, shadowColor, flooredIntSize(shadowOffset), shadowBlur, shadowSpread, clippedEdges);
         }
     }
 }
 
 } // namespace blink