[Layout API] Start converting ScrollAnchor to new layout API

third_party/WebKit/Source/core/layout/ScrollAnchor.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ScrollAnchor.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/UseCounter.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/line/InlineTextBox.h"
@@ skipping 10 matching lines @@
     , m_corner(Corner::TopLeft)
 {
     ASSERT(m_scroller);
     ASSERT(m_scroller->isFrameView() || m_scroller->isPaintLayerScrollableArea());
 }
 
 ScrollAnchor::~ScrollAnchor()
 {
 }
 
+// TODO(pilgrim) replace all instances of scrollerLayoutBox with scrollerLayoutBoxItem
+// https://crbug.com/499321
 static LayoutBox* scrollerLayoutBox(const ScrollableArea* scroller)
 {
     LayoutBox* box = scroller->isFrameView()
         ? toFrameView(scroller)->layoutView()
         : &toPaintLayerScrollableArea(scroller)->box();
     ASSERT(box);
     return box;
 }
 
+static LayoutBoxItem scrollerLayoutBoxItem(const ScrollableArea* scroller)
+{
+    LayoutBoxItem box = scroller->isFrameView()
+        ? toFrameView(scroller)->layoutViewItem()
+        : LayoutBoxItem(&toPaintLayerScrollableArea(scroller)->box());
+    ASSERT(!box.isNull());
+    return box;
+}
+
 static Corner cornerFromCandidateRect(LayoutRect candidateRect, LayoutRect visibleRect)
 {
     if (visibleRect.contains(candidateRect.minXMinYCorner()))
         return Corner::TopLeft;
     if (visibleRect.contains(candidateRect.maxXMinYCorner()))
         return Corner::TopRight;
     if (visibleRect.contains(candidateRect.minXMaxYCorner()))
         return Corner::BottomLeft;
     if (visibleRect.contains(candidateRect.maxXMaxYCorner()))
         return Corner::BottomRight;
@@ skipping 53 matching lines @@
     if (candidate->isLayoutInline())
         return ExamineResult(Continue);
 
     if (!candidate->isText() && !candidate->isBox())
         return ExamineResult(Skip);
 
     if (!candidateMovesWithScroller(candidate, m_scroller))
         return ExamineResult(Skip);
 
     LayoutRect candidateRect = relativeBounds(candidate, m_scroller);
-    LayoutRect visibleRect = scrollerLayoutBox(m_scroller)->overflowClipRect(LayoutPoint());
+    LayoutRect visibleRect = scrollerLayoutBoxItem(m_scroller).overflowClipRect(LayoutPoint());
 
     bool occupiesSpace = candidateRect.width() > 0 && candidateRect.height() > 0;
     if (occupiesSpace && visibleRect.intersects(candidateRect)) {
         return ExamineResult(
             visibleRect.contains(candidateRect) ? Return : Constrain,
             cornerFromCandidateRect(candidateRect, visibleRect));
     } else {
         return ExamineResult(Skip);
     }
 }
@@ skipping 74 matching lines @@
 void ScrollAnchor::clear()
 {
     LayoutObject* anchorObject = m_anchorObject;
     m_anchorObject = nullptr;
 
     if (anchorObject)
         anchorObject->maybeClearIsScrollAnchorObject();
 }
 
 } // namespace blink