Remove anonymous block wrapper when all children become inline

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
  * License as published by the Free Software Foundation; either
@@ skipping 624 matching lines @@
         return;
     parent->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::ChildAnonymousBlockChanged);
 
     child->moveAllChildrenTo(parent, child->nextSibling(), child->hasLayer());
     parent->setChildrenInline(child->childrenInline());
 
     parent->children()->removeChildNode(parent, child, child->hasLayer());
     child->destroy();
 }
 
-static inline bool shouldMakeChildrenInline(const LayoutBlock* block)
+void LayoutBlock::makeChildrenInlineIfPossible()
 {
-    if (!block->isLayoutBlockFlow())
-        return false;
-    LayoutObject* child = block->firstChild();
+    if (!isLayoutBlockFlow() || isRubyRun())

[mstensho (USE GERRIT), 2015/10/22 19:19:57]

Where does the ruby check come from? Do we have a test that would fail without
it?

+        return;
+    Vector<LayoutBox*, 16> blocksToRemove;

[mstensho (USE GERRIT), 2015/10/22 19:19:58]

How many anonymous blocks can we possibly find here? Two at most, right?

+    LayoutObject* child = firstChild();
     while (child) {
-        // TODO(rhogan): If we encounter anonymous blocks with inline children we should fold them in here.
-        if (!child->isFloatingOrOutOfFlowPositioned())
-            return false;
+        if (child->isAnonymousBlock() && child->childrenInline())
+            blocksToRemove.append(toLayoutBox(child));
+        else if (!child->isFloatingOrOutOfFlowPositioned())
+            return;
         child = child->nextSibling();
     }
-    return true;
+    for (size_t i = 0; i < blocksToRemove.size(); i++)
+        collapseAnonymousBlockChild(this, toLayoutBlock(blocksToRemove[i]));

[mstensho (USE GERRIT), 2015/10/22 19:19:58]

Looks like blocksToRemove should hold LayoutBlock pointers, so you don't need to
cast it here.

+    setChildrenInline(true);
 }
 
 void LayoutBlock::removeChild(LayoutObject* oldChild)
 {
     // No need to waste time in merging or removing empty anonymous blocks.
     // We can just bail out if our document is getting destroyed.
     if (documentBeingDestroyed()) {
         LayoutBox::removeChild(oldChild);
         return;
     }
@@ skipping 84 matching lines @@
                 else if (curr->isLayoutBlock())
                     toLayoutBlock(curr)->setContinuation(nextContinuation);
                 else
                     ASSERT_NOT_REACHED();
 
                 break;
             }
             setContinuation(nullptr);
             destroy();
         }
-    } else if (!beingDestroyed() && !oldChild->isFloatingOrOutOfFlowPositioned() && shouldMakeChildrenInline(this)) {
+    } else if (!beingDestroyed() && !oldChild->isFloatingOrOutOfFlowPositioned()) {
         // If the child we're removing means that we can now treat all children as inline without the need for anonymous blocks, then do that.
-        setChildrenInline(true);
+        makeChildrenInlineIfPossible();
     }
 }
 
 bool LayoutBlock::isSelfCollapsingBlock() const
 {
     // We are not self-collapsing if we
     // (a) have a non-zero height according to layout (an optimization to avoid wasting time)
     // (b) are a table,
     // (c) have border/padding,
     // (d) have a min-height
@@ skipping 2102 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink