Let RenderTable reach table cells needing overflow recalc

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 125225e68d42cbc446432ef57462f273d3e10bdc..bfc1391eaa8252f589d6155d61d341e8886cf5d3 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1609,18 +1609,25 @@ void RenderObject::setPseudoStyle(PassRefPtr<RenderStyle> pseudoStyle)
     setStyle(pseudoStyle);
 }
 
-void RenderObject::markContainingBlocksForOverflowRecalc()
+// FIXME: This will be markContainingBoxesForOverflowRecalc() when we make RenderBoxes recomputeOverflow-capable. crbug.com/437012.
+void RenderObject::markContainersForOverflowRecalcIfNeeded()

[Julien - ping for review, 2014/12/03 19:44:36]

As mentioned before, "container" has a meaning in rendering/ so it's better to
avoid using it. Better naming: markAncestorsForOverflowRecalcIfNeeded()

[Xianzhu, 2014/12/03 22:56:35]

Done.

 {
-    for (RenderBlock* container = containingBlock(); container && !container->childNeedsOverflowRecalcAfterStyleChange(); container = container->containingBlock())
-        container->setChildNeedsOverflowRecalcAfterStyleChange(true);
+    RenderObject* object = this;
+    do {
+        // Cell and row need to propagate the flag to their containing section and row as their containing block is the table wrapper.
+        // This enables us to only recompute overflow the modified sections / rows.
+        object = object->isTableCell() || object->isTableRow() ? object->parent() : object->containingBlock();
+        if (object)
+            object->setChildNeedsOverflowRecalcAfterStyleChange();
+    } while (object);
 }
 
 void RenderObject::setNeedsOverflowRecalcAfterStyleChange()
 {
     bool neededRecalc = needsOverflowRecalcAfterStyleChange();
-    setSelfNeedsOverflowRecalcAfterStyleChange(true);
+    setSelfNeedsOverflowRecalcAfterStyleChange();
     if (!neededRecalc)
-        markContainingBlocksForOverflowRecalc();
+        markContainersForOverflowRecalcIfNeeded();
 }
 
 void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
@@ -1822,7 +1829,7 @@ void RenderObject::styleDidChange(StyleDifference diff, const RenderStyle* oldSt
 
         // Ditto.
         if (needsOverflowRecalcAfterStyleChange() && oldStyle->position() != m_style->position())
-            markContainingBlocksForOverflowRecalc();
+            markContainersForOverflowRecalcIfNeeded();
 
         if (diff.needsFullLayout())
             setNeedsLayoutAndPrefWidthsRecalc();