[New Multicolumn] Actual support for layout of column-span:all.

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 ed9585fe0f2c3cdeaff5780f28c637af60d38eae..47beabdd7b8d58be6ac9f803f5bf758a41122de6 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -57,7 +57,6 @@
 #include "core/rendering/RenderCounter.h"
 #include "core/rendering/RenderDeprecatedFlexibleBox.h"
 #include "core/rendering/RenderFlexibleBox.h"
-#include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderGrid.h"
 #include "core/rendering/RenderImage.h"
@@ -65,6 +64,7 @@
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderListItem.h"
+#include "core/rendering/RenderMultiColumnFlowThread.h"
 #include "core/rendering/RenderObjectInlines.h"
 #include "core/rendering/RenderPart.h"
 #include "core/rendering/RenderScrollbarPart.h"
@@ -325,6 +325,13 @@ bool RenderObject::requiresAnonymousTableWrappers(const RenderObject* newChild)
     return false;
 }
 
+bool RenderObject::isValidColumnSpanAll() const
+{
+    ASSERT(style()->columnSpan() == ColumnSpanAll);
+    RenderFlowThread* flowThread = flowThreadContainingBlock();
+    return flowThread && flowThread->isColumnSpanner(this);
+}
+
 void RenderObject::addChild(RenderObject* newChild, RenderObject* beforeChild)
 {
     ASSERT(isAllowedToModifyRenderTreeStructure(document()));
@@ -634,7 +641,17 @@ RenderFlowThread* RenderObject::locateFlowThreadContainingBlock() const
     while (curr) {
         if (curr->isRenderFlowThread())
             return toRenderFlowThread(curr);
-        curr = curr->containingBlock();
+        switch (curr->style()->position()) {
+        case FixedPosition:
+            curr = curr->containerForFixedPosition();
+            break;
+        case AbsolutePosition:
+            curr = curr->containerForAbsolutePosition();
+            break;
+        default:
+            curr = curr->parentBlock();
+            break;
+        }
     }
     return 0;
 }
@@ -801,50 +818,69 @@ RenderBlock* RenderObject::containerForFixedPosition(const RenderLayerModelObjec
     return toRenderBlock(ancestor);
 }
 
-RenderBlock* RenderObject::containingBlock() const
+RenderBlock* RenderObject::containerForAbsolutePosition() const
 {
     RenderObject* o = parent();
-    if (!o && isRenderScrollbarPart())
-        o = toRenderScrollbarPart(this)->rendererOwningScrollbar();
-    if (!isText() && m_style->position() == FixedPosition) {
-        return containerForFixedPosition();
-    } else if (!isText() && m_style->position() == AbsolutePosition) {
-        while (o) {
-            // For relpositioned inlines, we return the nearest non-anonymous enclosing block. We don't try
-            // to return the inline itself.  This allows us to avoid having a positioned objects
-            // list in all RenderInlines and lets us return a strongly-typed RenderBlock* result
-            // from this method.  The container() method can actually be used to obtain the
-            // inline directly.
-            if (o->style()->position() != StaticPosition && (!o->isInline() || o->isReplaced()))
-                break;
-
-            if (o->canContainFixedPositionObjects())
-                break;
+    while (o) {
+        // For relpositioned inlines, we return the nearest non-anonymous enclosing block. We don't try
+        // to return the inline itself.  This allows us to avoid having a positioned objects
+        // list in all RenderInlines and lets us return a strongly-typed RenderBlock* result
+        // from this method.  The container() method can actually be used to obtain the
+        // inline directly.
+        if (o->style()->position() != StaticPosition && (!o->isInline() || o->isReplaced()))
+            break;
 
-            if (o->style()->hasInFlowPosition() && o->isInline() && !o->isReplaced()) {
-                o = o->containingBlock();
-                break;
-            }
+        if (o->canContainFixedPositionObjects())
+            break;
 
-            o = o->parent();
+        if (o->style()->hasInFlowPosition() && o->isInline() && !o->isReplaced()) {
+            o = o->parentBlock();
+            break;
         }
 
-        if (o && !o->isRenderBlock())
-            o = o->containingBlock();
-
-        while (o && o->isAnonymousBlock())
-            o = o->containingBlock();
-    } else {
-        while (o && ((o->isInline() && !o->isReplaced()) || !o->isRenderBlock()))
-            o = o->parent();
+        o = o->parent();
     }
 
+    if (o && !o->isRenderBlock())
+        o = o->parentBlock();
+
+    while (o && o->isAnonymousBlock())
+        o = o->parentBlock();
+
+    return toRenderBlock(o);
+}
+
+RenderBlock* RenderObject::parentBlock() const
+{
+    RenderObject* o = parent();
+    while (o && ((o->isInline() && !o->isReplaced()) || !o->isRenderBlock()))
+        o = o->parent();
+
     if (!o || !o->isRenderBlock())
         return 0; // This can still happen in case of an orphaned tree
 
     return toRenderBlock(o);
 }
 
+RenderBlock* RenderObject::containingBlock() const
+{
+    if (!parent() && isRenderScrollbarPart()) {
+        RenderObject* o = toRenderScrollbarPart(this)->rendererOwningScrollbar();
+        if (o && !o->isRenderBlock())
+            o = o->parentBlock();
+        return toRenderBlock(o);
+    }
+    if (!isText()) {
+        if (m_style->position() == FixedPosition)
+            return containerForFixedPosition();
+        if (m_style->position() == AbsolutePosition)
+            return containerForAbsolutePosition();
+    }
+    if (isColumnSpanAll())
+        return toRenderMultiColumnFlowThread(flowThreadContainingBlock())->multiColumnBlockFlow();
+    return parentBlock();
+}
+
 bool RenderObject::canRenderBorderImage() const
 {
     if (!style()->hasBorder())
@@ -2394,6 +2430,7 @@ void RenderObject::willBeRemovedFromTree()
         parent()->dirtyLinesFromChangedChild(this);
 
     removeFromRenderFlowThread();
+    RELEASE_ASSERT(!isColumnSpanAll()); // Former spanners should have been removed from the flow thread map by now.
 
     // Update cached boundaries in SVG renderers if a child is removed.
     if (parent()->isSVG())
@@ -2418,6 +2455,9 @@ void RenderObject::removeFromRenderFlowThreadRecursive(RenderFlowThread* renderF
         for (RenderObject* child = children->firstChild(); child; child = child->nextSibling())
             child->removeFromRenderFlowThreadRecursive(renderFlowThread);
     }
+
+    if (renderFlowThread && renderFlowThread != this)
+        renderFlowThread->flowThreadDescendantWillBeRemoved(this);
     setFlowThreadState(NotInsideFlowThread);
 }