[LayoutNG] Introduces NGPhysicalConstraintSpace and makes NGConstraintSpace a "view".

third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc

Index: third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc b/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc
index 4411e3b8035e3affc43af8ef7b828f27f36b13bd..14001f9e85d41a41a295b6fedf284694e79de5ab 100644
--- a/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc
+++ b/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.cc
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "core/layout/ng/layout_ng_block_flow.h"
-#include "core/layout/ng/ng_constraint_space.h"
+#include "core/layout/ng/ng_derived_constraint_space.h"
 #include "core/layout/ng/ng_block_layout_algorithm.h"
 #include "core/layout/ng/ng_box_iterator.h"
 #include "core/layout/ng/ng_fragment.h"
@@ -21,7 +21,8 @@ bool LayoutNGBlockFlow::isOfType(LayoutObjectType type) const {
 void LayoutNGBlockFlow::layoutBlock(bool relayoutChildren) {
   LayoutAnalyzer::BlockScope analyzer(*this);
 
-  const auto& constraintSpace = NGConstraintSpace::fromLayoutObject(*this);
+  const auto* constraintSpace =
+      NGDerivedConstraintSpace::CreateFromLayoutObject(*this);
   NGBox box(this);
   box.layout(constraintSpace);
   clearNeedsLayout();