Use Layout Opportunity Iterator to position new FC blocks.

third_party/WebKit/Source/core/layout/ng/ng_floating_object.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NGFloatingObject_h
 #define NGFloatingObject_h
 
 #include "core/layout/ng/geometry/ng_box_strut.h"
 #include "core/layout/ng/geometry/ng_logical_size.h"
 #include "core/layout/ng/ng_block_node.h"
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_exclusion.h"
 #include "core/layout/ng/ng_physical_fragment.h"
 #include "core/style/ComputedStyle.h"
 #include "core/style/ComputedStyleConstants.h"
+#include "platform/wtf/Optional.h"
 #include "platform/wtf/RefPtr.h"
 
 namespace blink {
 
 // Struct that keeps all information needed to position floats in LayoutNG.
 struct CORE_EXPORT NGFloatingObject : public RefCounted<NGFloatingObject> {
  public:
   static RefPtr<NGFloatingObject> Create(const ComputedStyle& style,
                                          NGWritingMode writing_mode,
                                          NGLogicalSize available_size,
@@ skipping 17 matching lines @@
   // - origin_offset which represents the layout point for this float.
   // - from_offset which represents the point from where we need to calculate
   //   the relative logical offset for this float.
   // Layout details:
   // At the time when this float is created only *inline* offsets are known.
   // Block offset will be set when we are about to place this float, i.e. when
   // we resolved MarginStrut, adjusted the offset to clearance line etc.
   NGLogicalOffset origin_offset;
   NGLogicalOffset from_offset;
 
+  // Calculated logical offset. It's never {@code nullopt} for a positioned
+  // float.
+  WTF::Optional<NGLogicalOffset> logical_offset;
+
   // Writing mode of the float's constraint space.
   NGWritingMode writing_mode;
 
   RefPtr<NGPhysicalFragment> fragment;
 
   // In the case where a legacy FloatingObject is attached to not its own
   // parent, e.g. a float surrounded by a bunch of nested empty divs,
   // NG float fragment's LeftOffset() cannot be used as legacy FloatingObject's
   // left offset because that offset should be relative to the original float
   // parent.
@@ skipping 27 matching lines @@
     exclusion_type = NGExclusion::kFloatLeft;
     if (style.Floating() == EFloat::kRight)
       exclusion_type = NGExclusion::kFloatRight;
     clear_type = style.Clear();
   }
 };
 
 }  // namespace blink
 
 #endif  // NGFloatingObject_h