Return refererence from InlineBox::root()

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 760eab0aad7d7832b5fed5c1e2a2aff48cfc7088..ce57184643479aff6fb5fe357bc1802a60cded46 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -1956,8 +1956,8 @@ void RenderBox::positionLineBox(InlineBox* box)
             // The value is cached in the xPos of the box.  We only need this value if
             // our object was inline originally, since otherwise it would have ended up underneath
             // the inlines.
-            RootInlineBox* root = box->root();
-            root->block().setStaticInlinePositionForChild(this, root->lineTopWithLeading(), LayoutUnit::fromFloatRound(box->logicalLeft()));
+            RootInlineBox& root = box->root();
+            root.block().setStaticInlinePositionForChild(this, root.lineTopWithLeading(), LayoutUnit::fromFloatRound(box->logicalLeft()));
             if (style()->hasStaticInlinePosition(box->isHorizontal()))
                 setChildNeedsLayout(MarkOnlyThis); // Just go ahead and mark the positioned object as needing layout, so it will update its position properly.
         } else {
@@ -4013,10 +4013,10 @@ LayoutRect RenderBox::localCaretRect(InlineBox* box, int caretOffset, LayoutUnit
         rect.move(LayoutSize(width() - caretWidth, 0));
 
     if (box) {
-        RootInlineBox* rootBox = box->root();
-        LayoutUnit top = rootBox->lineTop();
+        RootInlineBox& rootBox = box->root();
+        LayoutUnit top = rootBox.lineTop();
         rect.setY(top);
-        rect.setHeight(rootBox->lineBottom() - top);
+        rect.setHeight(rootBox.lineBottom() - top);
     }
 
     // If height of box is smaller than font height, use the latter one,