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

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

Index: third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.h b/third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.h
index 5899531685560886fbf6bf0ad5b8638ca865d61c..c2d626b9c3d754c6ae1cb4116597d14da5ee80ad 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_physical_fragment.h
@@ -33,6 +33,8 @@ class CORE_EXPORT NGPhysicalFragment : public RefCounted<NGPhysicalFragment> {
   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.