blink: Cleanup class/struct forward declarations

third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.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 NGLayoutAlgorithm_h
 #define NGLayoutAlgorithm_h
 
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Allocator.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 struct MinAndMaxContentSizes;
 class NGBlockNode;
 class NGConstraintSpace;
 class NGFragmentBase;
 class NGPhysicalFragmentBase;
-class NGPhysicalFragment;
 
 enum NGLayoutStatus { kNotFinished, kChildAlgorithmRequired, kNewFragment };
 
 // Base class for all LayoutNG algorithms.
 class CORE_EXPORT NGLayoutAlgorithm
     : public GarbageCollectedFinalized<NGLayoutAlgorithm> {
   WTF_MAKE_NONCOPYABLE(NGLayoutAlgorithm);
 
  public:
   NGLayoutAlgorithm() {}
@@ skipping 26 matching lines @@
   virtual MinAndMaxState ComputeMinAndMaxContentSizes(MinAndMaxContentSizes*) {
     return kNotImplemented;
   }
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 };
 
 }  // namespace blink
 
 #endif  // NGLayoutAlgorithm_h