[LayoutNG] Allow block-flow layout to be fragmented using new approach.

third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.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 NGPhysicalFragment_h
 #define NGPhysicalFragment_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_units.h"
 #include "platform/LayoutUnit.h"
@@ skipping 15 matching lines @@
 // such that paint/hit-testing/etc don't modify it.
 //
 // Layout code should only access geometry information through the
 // NGFragment wrapper classes which transforms information into the logical
 // coordinate system.
 class CORE_EXPORT NGPhysicalFragment : public RefCounted<NGPhysicalFragment> {
  public:
   enum NGFragmentType { kFragmentBox = 0, kFragmentText = 1 };
 
   NGFragmentType Type() const { return static_cast<NGFragmentType>(type_); }
+  bool IsBox() const { return Type() == NGFragmentType::kFragmentBox; }
+  bool IsText() const { return Type() == NGFragmentType::kFragmentText; }
 
   // Override RefCounted's deref() to ensure operator delete is called on the
   // appropriate subclass type.
   void deref() const {
     if (derefBase())
       destroy();
   }
 
   // The accessors in this class shouldn't be used by layout code directly,
   // instead should be accessed by the NGFragmentBase classes. These accessors
@@ skipping 57 matching lines @@
   unsigned type_ : 1;
   unsigned is_placed_ : 1;
 
  private:
   void destroy() const;
 };
 
 }  // namespace blink
 
 #endif  // NGPhysicalFragment_h