Avoid layout/full-repaint on view height change if possible

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index c7a42b6d2d8804f60cd07a557c784accdc880b38..c25af607c46f075e4f27ab11b052650598aa9058 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -2856,8 +2856,8 @@ LayoutUnit RenderBox::computePercentageLogicalHeight(const Length& height) const
         skippedAutoHeightContainingBlock = true;
         containingBlockChild = cb;
         cb = cb->containingBlock();
-        cb->addPercentHeightDescendant(const_cast<RenderBox*>(this));
     }
+    cb->addPercentHeightDescendant(const_cast<RenderBox*>(this));
 
     RenderStyle* cbstyle = cb->style();
 
@@ -3009,10 +3009,10 @@ LayoutUnit RenderBox::computeReplacedLogicalHeightUsing(Length logicalHeight) co
         case Calculated:
         {
             RenderObject* cb = isOutOfFlowPositioned() ? container() : containingBlock();
-            while (cb->isAnonymous()) {
+            while (cb->isAnonymous())
                 cb = cb->containingBlock();
+            if (cb->isRenderBlock())
                 toRenderBlock(cb)->addPercentHeightDescendant(const_cast<RenderBox*>(this));
-            }
 
             // FIXME: This calculation is not patched for block-flow yet.
             // https://bugs.webkit.org/show_bug.cgi?id=46500