[layoutng] Split NGLayoutResult out of NGPhysicalFragment

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

+// Copyright 2017 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 NGLayoutResult_h
+#define NGLayoutResult_h
+
+#include "core/CoreExport.h"
+#include "core/layout/ng/ng_physical_fragment.h"
+#include "core/layout/ng/ng_units.h"
+#include "platform/LayoutUnit.h"
+#include "platform/heap/Handle.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class LayoutObject;
+class NGPhysicalFragment;
+class NGBlockNode;
+struct NGFloatingObject;
+
+// The NGLayoutResult stores the resulting data from layout. This includes

[eae, 2017/02/21 22:39:05]

NGLayoutContext or NGLayoutIntermediate Result might be better names? Up to you.

[ikilpatrick, 2017/02/21 22:48:55]

I'm a fan of NGLayoutResult, as this is the unit that we'll be caching. Context
is hyper overloaded term, i'd be against that :)

+// geometry information in form of a NGPhysicalFragment, which is kept around
+// for painting, hit testingm etc., as well as additional data which is only
+// necessary doing layout and stored on this object.

[eae, 2017/02/21 22:39:05]

s/doing/during?

+// Layout code should access the NGPhysicalFragment through the wrappers in
+// NGFragment et al.
+class CORE_EXPORT NGLayoutResult : public RefCounted<NGLayoutResult> {
+ public:
+  RefPtr<NGPhysicalFragment> PhysicalFragment() const {
+    return physical_fragment_;
+  }
+
+  const HeapLinkedHashSet<WeakMember<NGBlockNode>>& OutOfFlowDescendants()
+      const {
+    return out_of_flow_descendants_;
+  }
+
+  const Vector<NGStaticPosition>& OutOfFlowPositions() const {
+    return out_of_flow_positions_;
+  }
+
+  // List of floats that need to be positioned by the next in-flow child that
+  // can determine its position in space.
+  // Use case example where it may be needed:
+  //    <div><float></div>
+  //    <div style="margin-top: 10px; height: 20px"></div>
+  // The float cannot be positioned right away inside of the 1st div because
+  // the vertical position is not known at that moment. It will be known only
+  // after the 2nd div collapses its margin with its parent.
+  const Vector<Persistent<NGFloatingObject>>& UnpositionedFloats() const {
+    return unpositioned_floats_;
+  }
+
+ private:
+  friend class NGFragmentBuilder;
+
+  NGLayoutResult(PassRefPtr<NGPhysicalFragment> physical_fragment,
+                 PersistentHeapLinkedHashSet<WeakMember<NGBlockNode>>&
+                     out_of_flow_descendants,
+                 Vector<NGStaticPosition> out_of_flow_positions,
+                 Vector<Persistent<NGFloatingObject>>& unpositioned_floats);
+
+  RefPtr<NGPhysicalFragment> physical_fragment_;
+  LayoutObject* layout_object_;
+  PersistentHeapLinkedHashSet<WeakMember<NGBlockNode>> out_of_flow_descendants_;
+  Vector<NGStaticPosition> out_of_flow_positions_;
+  Vector<Persistent<NGFloatingObject>> unpositioned_floats_;
+};
+
+}  // namespace blink
+
+#endif  // NGLayoutResult_h