Avoid unnecessary descents into nested boxes with floats.

Source/core/rendering/RenderBlock.h

Index: Source/core/rendering/RenderBlock.h
diff --git a/Source/core/rendering/RenderBlock.h b/Source/core/rendering/RenderBlock.h
index ef98d8d896ba727a2fc68f40a1275835f458df76..150ca543863918b0bc1449b76d750afe517c593a 100644
--- a/Source/core/rendering/RenderBlock.h
+++ b/Source/core/rendering/RenderBlock.h
@@ -531,13 +531,14 @@ protected:
     RenderObjectChildList m_children;
     RenderLineBoxList m_lineBoxes;   // All of the root line boxes created for this block flow.  For example, <div>Hello<br>world.</div> will have two total lines for the <div>.
 
-    mutable signed m_lineHeight : 26;
+    mutable signed m_lineHeight : 25;
     unsigned m_hasMarginBeforeQuirk : 1; // Note these quirk values can't be put in RenderBlockRareData since they are set too frequently.
     unsigned m_hasMarginAfterQuirk : 1;
     unsigned m_beingDestroyed : 1;
     unsigned m_hasMarkupTruncation : 1;
     unsigned m_hasBorderOrPaddingLogicalWidthChanged : 1;
     mutable unsigned m_hasOnlySelfCollapsingChildren : 1;
+    mutable unsigned m_descendantsWithFloatsMarkedForLayout : 1;
 
     // RenderRubyBase objects need to be able to split and merge, moving their children around
     // (calling moveChildTo, moveAllChildrenTo, and makeChildrenNonInline).