Fold out-of-flow objects into anonymous blocks when removing children

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

Index: third_party/WebKit/Source/core/layout/LayoutBlock.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
index 0cea0eb22dae2576fade4e41ee74a0fa4bd7d5a5..64deb6b694a61cacae88910ea5c607abc3da429a 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
@@ -375,6 +375,26 @@ void LayoutBlock::invalidateDisplayItemClients(const LayoutBoxModelObject& paint
     invalidateDisplayItemClientForStartOfContinuationsIfNeeded(*this);
 }
 
+static void addNextFloatingOrOutOfFlowSiblingsToBlock(LayoutBlock* block, LayoutBlock* container)
+{
+    LayoutObject* child = block->nextSibling();
+    while (child && child->isFloatingOrOutOfFlowPositioned()) {
+        LayoutObject* sibling = child->nextSibling();
+        container->moveChildTo(block, child, nullptr, false);
+        child = sibling;
+    }
+}
+
+static void addPreviousFloatingOrOutOfFlowSiblingsToBlock(LayoutBlock* block, LayoutBlock* container)
+{
+    LayoutObject* child = block->previousSibling();
+    while (child && child->isFloatingOrOutOfFlowPositioned()) {
+        LayoutObject* sibling = child->previousSibling();
+        container->moveChildTo(block, child, block->firstChild(), false);
+        child = sibling;
+    }
+}
+
 void LayoutBlock::addChildIgnoringContinuation(LayoutObject* newChild, LayoutObject* beforeChild)
 {
     if (beforeChild && beforeChild->parent() != this) {
@@ -449,19 +469,9 @@ void LayoutBlock::addChildIgnoringContinuation(LayoutObject* newChild, LayoutObj
             LayoutBlock* newBox = createAnonymousBlock();
             LayoutBox::addChild(newBox, beforeChild);
             // Reparent adjacent floating or out-of-flow siblings to the new box.
-            LayoutObject* child = newBox->previousSibling();
-            while (child && child->isFloatingOrOutOfFlowPositioned()) {
-                LayoutObject* sibling = child->previousSibling();
-                moveChildTo(newBox, child, newBox->firstChild(), false);
-                child = sibling;
-            }
+            addPreviousFloatingOrOutOfFlowSiblingsToBlock(newBox, this);
             newBox->addChild(newChild);
-            child = newBox->nextSibling();
-            while (child && child->isFloatingOrOutOfFlowPositioned()) {
-                LayoutObject* sibling = child->nextSibling();
-                moveChildTo(newBox, child, nullptr, false);
-                child = sibling;
-            }
+            addNextFloatingOrOutOfFlowSiblingsToBlock(newBox, this);
             return;
         }
     }
@@ -728,6 +738,13 @@ void LayoutBlock::removeChild(LayoutObject* oldChild)
             && (!anonymousBlock->previousSibling() || (anonymousBlock->previousSibling()->style()->styleType() != NOPSEUDO && anonymousBlock->previousSibling()->isFloating() && !anonymousBlock->previousSibling()->previousSibling()))
             && (!anonymousBlock->nextSibling() || (anonymousBlock->nextSibling()->style()->styleType() != NOPSEUDO && anonymousBlock->nextSibling()->isFloating() && !anonymousBlock->nextSibling()->nextSibling()))) {
             collapseAnonymousBlockChild(this, anonymousBlock);
+        } else {
+            // If we have floating or out-of-flow siblings now adjacent to an anonymous block, fold them
+            // into it.
+            if (prev && prev->isAnonymousBlock())
+                addNextFloatingOrOutOfFlowSiblingsToBlock(toLayoutBlock(prev), this);
+            else if (next && next->isAnonymousBlock())
+                addPreviousFloatingOrOutOfFlowSiblingsToBlock(toLayoutBlock(next), this);
         }
     }