Dispel the myth that enclosingLayer can return zero

Source/core/rendering/RenderBlock.cpp

Index: Source/core/rendering/RenderBlock.cpp
diff --git a/Source/core/rendering/RenderBlock.cpp b/Source/core/rendering/RenderBlock.cpp
index e452f1c3e67653fb41541bb145846faaeac73b7f..52a004f3644935f3f3e4fddc091a5c806ba73a1f 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -2349,17 +2349,16 @@ void RenderBlock::paintSelection(PaintInfo& paintInfo, const LayoutPoint& paintO
 
         LayoutRect gapRectsBounds = selectionGaps(this, paintOffset, LayoutSize(), lastTop, lastLeft, lastRight, &paintInfo);
         if (!gapRectsBounds.isEmpty()) {
-            if (RenderLayer* layer = enclosingLayer()) {
-                gapRectsBounds.moveBy(-paintOffset);
-                if (!hasLayer()) {
-                    LayoutRect localBounds(gapRectsBounds);
-                    flipForWritingMode(localBounds);
-                    gapRectsBounds = localToContainerQuad(FloatRect(localBounds), layer->renderer()).enclosingBoundingBox();
-                    if (layer->renderer()->hasOverflowClip())
-                        gapRectsBounds.move(layer->renderBox()->scrolledContentOffset());
-                }
-                layer->addBlockSelectionGapsBounds(gapRectsBounds);
+            RenderLayer* layer = enclosingLayer();
+            gapRectsBounds.moveBy(-paintOffset);
+            if (!hasLayer()) {
+                LayoutRect localBounds(gapRectsBounds);
+                flipForWritingMode(localBounds);
+                gapRectsBounds = localToContainerQuad(FloatRect(localBounds), layer->renderer()).enclosingBoundingBox();
+                if (layer->renderer()->hasOverflowClip())
+                    gapRectsBounds.move(layer->renderBox()->scrolledContentOffset());
             }
+            layer->addBlockSelectionGapsBounds(gapRectsBounds);
         }
     }
 }