Use tighter typing in table rendering code

Source/core/rendering/RenderTableRow.cpp

Index: Source/core/rendering/RenderTableRow.cpp
diff --git a/Source/core/rendering/RenderTableRow.cpp b/Source/core/rendering/RenderTableRow.cpp
index 8a41cc73839af44d50e0c00ffa785e0a497123b2..7e4557f8d9a450e358a647500a0f574a671c7b94 100644
--- a/Source/core/rendering/RenderTableRow.cpp
+++ b/Source/core/rendering/RenderTableRow.cpp
@@ -1,10 +1,10 @@
-/**
+/*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
- * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
+ * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -111,7 +111,7 @@ void RenderTableRow::addChild(RenderObject* child, RenderObject* beforeChild)
     if (!child->isTableCell()) {
         RenderObject* last = beforeChild;
         if (!last)
-            last = lastChild();
+            last = lastCell();
         if (last && last->isAnonymous() && last->isTableCell() && !last->isBeforeOrAfterContent()) {
             RenderTableCell* lastCell = toRenderTableCell(last);
             if (beforeChild == lastCell)
@@ -152,7 +152,7 @@ void RenderTableRow::addChild(RenderObject* child, RenderObject* beforeChild)
     ASSERT(!beforeChild || beforeChild->isTableCell());
     RenderBox::addChild(cell, beforeChild);
 
-    if (beforeChild || nextSibling())
+    if (beforeChild || nextRow())
         section()->setNeedsCellRecalc();
 }
 
@@ -163,16 +163,13 @@ void RenderTableRow::layout()
     // Table rows do not add translation.
     LayoutStateMaintainer statePusher(*this, LayoutSize());
 
-    for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
-        if (child->isTableCell()) {
-            SubtreeLayoutScope layouter(*child);
-            RenderTableCell* cell = toRenderTableCell(child);
-            if (!cell->needsLayout())
-                cell->markForPaginationRelayoutIfNeeded(layouter);
-            if (cell->needsLayout()) {
-                cell->computeAndSetBlockDirectionMargins(table());
-                cell->layout();
-            }
+    for (RenderTableCell* cell = firstCell(); cell; cell = cell->nextCell()) {
+        SubtreeLayoutScope layouter(*cell);
+        if (!cell->needsLayout())
+            cell->markForPaginationRelayoutIfNeeded(layouter);
+        if (cell->needsLayout()) {
+            cell->computeAndSetBlockDirectionMargins(table());
+            cell->layout();
         }
     }
 
@@ -185,14 +182,12 @@ void RenderTableRow::layout()
     // We cannot call repaint() because our clippedOverflowRectForRepaint() is taken from the
     // parent table, and being mid-layout, that is invalid. Instead, we repaint our cells.
     if (selfNeedsLayout() && checkForRepaint()) {
-        for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
-            if (child->isTableCell()) {
-                if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
-                    // FIXME: Is this needed with repaint After Layout?
-                    child->setShouldDoFullRepaintAfterLayout(true);
-                } else {
-                    child->repaint();
-                }
+        for (RenderTableCell* cell = firstCell(); cell; cell = cell->nextCell()) {
+            if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
+                // FIXME: Is this needed with repaint After Layout?
+                cell->setShouldDoFullRepaintAfterLayout(true);
+            } else {
+                cell->repaint();
             }
         }
     }
@@ -206,14 +201,14 @@ bool RenderTableRow::nodeAtPoint(const HitTestRequest& request, HitTestResult& r
 {
     // Table rows cannot ever be hit tested.  Effectively they do not exist.
     // Just forward to our children always.
-    for (RenderObject* child = lastChild(); child; child = child->previousSibling()) {
+    for (RenderTableCell* cell = lastCell(); cell; cell = cell->previousCell()) {
         // FIXME: We have to skip over inline flows, since they can show up inside table rows
         // at the moment (a demoted inline <form> for example). If we ever implement a
         // table-specific hit-test method (which we should do for performance reasons anyway),
         // then we can remove this check.
-        if (child->isTableCell() && !toRenderBox(child)->hasSelfPaintingLayer()) {
-            LayoutPoint cellPoint = flipForWritingModeForChild(toRenderTableCell(child), accumulatedOffset);
-            if (child->nodeAtPoint(request, result, locationInContainer, cellPoint, action)) {
+        if (!cell->hasSelfPaintingLayer()) {
+            LayoutPoint cellPoint = flipForWritingModeForChild(cell, accumulatedOffset);
+            if (cell->nodeAtPoint(request, result, locationInContainer, cellPoint, action)) {
                 updateHitTestResult(result, locationInContainer.point() - toLayoutSize(cellPoint));
                 return true;
             }
@@ -237,16 +232,12 @@ void RenderTableRow::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
     ANNOTATE_GRAPHICS_CONTEXT(paintInfo, this);
 
     paintOutlineForRowIfNeeded(paintInfo, paintOffset);
-    for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
-        if (child->isTableCell()) {
-            // Paint the row background behind the cell.
-            if (paintInfo.phase == PaintPhaseBlockBackground || paintInfo.phase == PaintPhaseChildBlockBackground) {
-                RenderTableCell* cell = toRenderTableCell(child);
-                cell->paintBackgroundsBehindCell(paintInfo, paintOffset, this);
-            }
-            if (!toRenderBox(child)->hasSelfPaintingLayer())
-                child->paint(paintInfo, paintOffset);
-        }
+    for (RenderTableCell* cell = firstCell(); cell; cell = cell->nextCell()) {
+        // Paint the row background behind the cell.
+        if (paintInfo.phase == PaintPhaseBlockBackground || paintInfo.phase == PaintPhaseChildBlockBackground)
+            cell->paintBackgroundsBehindCell(paintInfo, paintOffset, this);
+        if (!cell->hasSelfPaintingLayer())
+            cell->paint(paintInfo, paintOffset);
     }
 }