[layoutng] async layout part 1: Change the API to support async

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 14001f9e85d41a41a295b6fedf284694e79de5ab..45a8cf6bb7c6536de324d1ad6d399dafeebdbf01 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
@@ -21,10 +21,12 @@ bool LayoutNGBlockFlow::isOfType(LayoutObjectType type) const {
 void LayoutNGBlockFlow::layoutBlock(bool relayoutChildren) {
   LayoutAnalyzer::BlockScope analyzer(*this);
 
-  const auto* constraintSpace =
+  const auto* constraint_space =
       NGDerivedConstraintSpace::CreateFromLayoutObject(*this);
   NGBox box(this);
-  box.layout(constraintSpace);
+  NGFragment* fragment;
+  while (!box.Layout(constraint_space, &fragment))
+    ;
   clearNeedsLayout();
 }