Remove CSS regions support, keeping a bare minimum to support "region-based" multicol.

Source/core/rendering/RenderDeprecatedFlexibleBox.cpp

Index: Source/core/rendering/RenderDeprecatedFlexibleBox.cpp
diff --git a/Source/core/rendering/RenderDeprecatedFlexibleBox.cpp b/Source/core/rendering/RenderDeprecatedFlexibleBox.cpp
index 2844834392c84d7761304d4f088e8ef0c57da3aa..676a73593a766bcb522252b3d19d69d322cfef08 100644
--- a/Source/core/rendering/RenderDeprecatedFlexibleBox.cpp
+++ b/Source/core/rendering/RenderDeprecatedFlexibleBox.cpp
@@ -260,10 +260,7 @@ void RenderDeprecatedFlexibleBox::layoutBlock(bool relayoutChildren)
     LayoutRepainter repainter(*this, checkForRepaintDuringLayout());
     LayoutStateMaintainer statePusher(view(), this, locationOffset(), hasTransform() || hasReflection() || style()->isFlippedBlocksWritingMode());
 
-    // Regions changing widths can force us to relayout our children.
     RenderFlowThread* flowThread = flowThreadContainingBlock();
-    if (logicalWidthChangedInRegions(flowThread))
-        relayoutChildren = true;
     if (updateRegionsAndShapesLogicalSize(flowThread))
         relayoutChildren = true;
 
@@ -426,7 +423,7 @@ void RenderDeprecatedFlexibleBox::layoutHorizontalBox(bool relayoutChildren)
             if (child->isOutOfFlowPositioned()) {
                 child->containingBlock()->insertPositionedObject(child);
                 RenderLayer* childLayer = child->layer();
-                childLayer->setStaticInlinePosition(xPos); // FIXME: Not right for regions.
+                childLayer->setStaticInlinePosition(xPos);
                 if (childLayer->staticBlockPosition() != yPos) {
                     childLayer->setStaticBlockPosition(yPos);
                     if (child->style()->hasStaticBlockPosition(style()->isHorizontalWritingMode()))
@@ -664,7 +661,7 @@ void RenderDeprecatedFlexibleBox::layoutVerticalBox(bool relayoutChildren)
             if (child->isOutOfFlowPositioned()) {
                 child->containingBlock()->insertPositionedObject(child);
                 RenderLayer* childLayer = child->layer();
-                childLayer->setStaticInlinePosition(borderStart() + paddingStart()); // FIXME: Not right for regions.
+                childLayer->setStaticInlinePosition(borderStart() + paddingStart());
                 if (childLayer->staticBlockPosition() != height()) {
                     childLayer->setStaticBlockPosition(height());
                     if (child->style()->hasStaticBlockPosition(style()->isHorizontalWritingMode()))