Enable new multicol for testing and experimental web platform features.

Source/core/paint/ViewPainter.cpp

Index: Source/core/paint/ViewPainter.cpp
diff --git a/Source/core/paint/ViewPainter.cpp b/Source/core/paint/ViewPainter.cpp
index 78fb52defd6958b20d9ac90b88f0036980b70fab..32631ef100603270f02d1b7c15c7c38351b6c96b 100644
--- a/Source/core/paint/ViewPainter.cpp
+++ b/Source/core/paint/ViewPainter.cpp
@@ -12,6 +12,7 @@
 #include "core/paint/GraphicsContextAnnotator.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
 #include "core/paint/PaintInfo.h"
+#include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
@@ -26,7 +27,7 @@ void ViewPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffs
 
     // This avoids painting garbage between columns if there is a column gap.
     // This is legacy WebKit behavior and doesn't work with slimmingpaint. We can remove it once region-based columns are launched.
-    if (!m_layoutView.document().regionBasedColumnsEnabled() && m_layoutView.frameView() && m_layoutView.style()->isOverflowPaged()) {
+    if (!RuntimeEnabledFeatures::regionBasedColumnsEnabled() && m_layoutView.frameView() && m_layoutView.style()->isOverflowPaged()) {
         ASSERT(!RuntimeEnabledFeatures::slimmingPaintEnabled());
         LayoutRect paintRect(paintInfo.rect);
         paintInfo.context->fillRect(paintRect, m_layoutView.frameView()->baseBackgroundColor());