Return refererence from InlineBox::root()

Source/core/rendering/RenderLineBoxList.cpp

Index: Source/core/rendering/RenderLineBoxList.cpp
diff --git a/Source/core/rendering/RenderLineBoxList.cpp b/Source/core/rendering/RenderLineBoxList.cpp
index 085224721fe2d175df4b04089b452329bc0eea4c..db990d8402f7a100cc9f6e7c81517e181b7d6d98 100644
--- a/Source/core/rendering/RenderLineBoxList.cpp
+++ b/Source/core/rendering/RenderLineBoxList.cpp
@@ -176,10 +176,10 @@ bool RenderLineBoxList::anyLineIntersectsRect(RenderBoxModelObject* renderer, co
     // intersect.  This is a quick short-circuit that we can take to avoid walking any lines.
     // FIXME: This check is flawed in the following extremely obscure way:
     // if some line in the middle has a huge overflow, it might actually extend below the last line.
-    RootInlineBox* firstRootBox = firstLineBox()->root();
-    RootInlineBox* lastRootBox = lastLineBox()->root();
-    LayoutUnit firstLineTop = firstLineBox()->logicalTopVisualOverflow(firstRootBox->lineTop());
-    LayoutUnit lastLineBottom = lastLineBox()->logicalBottomVisualOverflow(lastRootBox->lineBottom());
+    RootInlineBox& firstRootBox = firstLineBox()->root();
+    RootInlineBox& lastRootBox = lastLineBox()->root();
+    LayoutUnit firstLineTop = firstLineBox()->logicalTopVisualOverflow(firstRootBox.lineTop());
+    LayoutUnit lastLineBottom = lastLineBox()->logicalBottomVisualOverflow(lastRootBox.lineBottom());
     LayoutUnit logicalTop = firstLineTop - outlineSize;
     LayoutUnit logicalBottom = outlineSize + lastLineBottom;
 
@@ -188,9 +188,9 @@ bool RenderLineBoxList::anyLineIntersectsRect(RenderBoxModelObject* renderer, co
 
 bool RenderLineBoxList::lineIntersectsDirtyRect(RenderBoxModelObject* renderer, InlineFlowBox* box, const PaintInfo& paintInfo, const LayoutPoint& offset) const
 {
-    RootInlineBox* root = box->root();
-    LayoutUnit logicalTop = min<LayoutUnit>(box->logicalTopVisualOverflow(root->lineTop()), root->selectionTop()) - renderer->maximalOutlineSize(paintInfo.phase);
-    LayoutUnit logicalBottom = box->logicalBottomVisualOverflow(root->lineBottom()) + renderer->maximalOutlineSize(paintInfo.phase);
+    RootInlineBox& root = box->root();
+    LayoutUnit logicalTop = min<LayoutUnit>(box->logicalTopVisualOverflow(root.lineTop()), root.selectionTop()) - renderer->maximalOutlineSize(paintInfo.phase);
+    LayoutUnit logicalBottom = box->logicalBottomVisualOverflow(root.lineBottom()) + renderer->maximalOutlineSize(paintInfo.phase);
 
     return rangeIntersectsRect(renderer, logicalTop, logicalBottom, paintInfo.rect, offset);
 }
@@ -222,8 +222,8 @@ void RenderLineBoxList::paint(RenderBoxModelObject* renderer, PaintInfo& paintIn
     // based off positions of our first line box or our last line box.
     for (InlineFlowBox* curr = firstLineBox(); curr; curr = curr->nextLineBox()) {
         if (lineIntersectsDirtyRect(renderer, curr, info, paintOffset)) {
-            RootInlineBox* root = curr->root();
-            curr->paint(info, paintOffset, root->lineTop(), root->lineBottom());
+            RootInlineBox& root = curr->root();
+            curr->paint(info, paintOffset, root.lineTop(), root.lineBottom());
         }
     }
 
@@ -260,9 +260,9 @@ bool RenderLineBoxList::hitTest(RenderBoxModelObject* renderer, const HitTestReq
     // them further.  Note that boxes can easily overlap, so we can't make any assumptions
     // based off positions of our first line box or our last line box.
     for (InlineFlowBox* curr = lastLineBox(); curr; curr = curr->prevLineBox()) {
-        RootInlineBox* root = curr->root();
-        if (rangeIntersectsRect(renderer, curr->logicalTopVisualOverflow(root->lineTop()), curr->logicalBottomVisualOverflow(root->lineBottom()), rect, accumulatedOffset)) {
-            bool inside = curr->nodeAtPoint(request, result, locationInContainer, accumulatedOffset, root->lineTop(), root->lineBottom());
+        RootInlineBox& root = curr->root();
+        if (rangeIntersectsRect(renderer, curr->logicalTopVisualOverflow(root.lineTop()), curr->logicalBottomVisualOverflow(root.lineBottom()), rect, accumulatedOffset)) {
+            bool inside = curr->nodeAtPoint(request, result, locationInContainer, accumulatedOffset, root.lineTop(), root.lineBottom());
             if (inside) {
                 renderer->updateHitTestResult(result, locationInContainer.point() - toLayoutSize(accumulatedOffset));
                 return true;
@@ -304,15 +304,15 @@ void RenderLineBoxList::dirtyLinesFromChangedChild(RenderObject* container, Rend
         if (curr->isReplaced()) {
             InlineBox* wrapper = toRenderBox(curr)->inlineBoxWrapper();
             if (wrapper)
-                box = wrapper->root();
+                box = &wrapper->root();
         } else if (curr->isText()) {
             InlineTextBox* textBox = toRenderText(curr)->lastTextBox();
             if (textBox)
-                box = textBox->root();
+                box = &textBox->root();
         } else if (curr->isRenderInline()) {
             InlineBox* lastSiblingBox = toRenderInline(curr)->lastLineBoxIncludingCulling();
             if (lastSiblingBox)
-                box = lastSiblingBox->root();
+                box = &lastSiblingBox->root();
         }
 
         if (box)
@@ -331,7 +331,7 @@ void RenderLineBoxList::dirtyLinesFromChangedChild(RenderObject* container, Rend
             }
             return;
         }
-        box = firstBox->root();
+        box = &firstBox->root();
     }
 
     // If we found a line box, then dirty it.