Use Layout Opportunity Iterator to position new FC blocks.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_layout_input_node.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_layout_input_node.h b/third_party/WebKit/Source/core/layout/ng/ng_layout_input_node.h
index be10d87903bcb93a818bbd1364026693371c8a22..25b30c705c57aabd1a84595cda7872a8ac777d9b 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_layout_input_node.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_layout_input_node.h
@@ -6,11 +6,11 @@
 #define NGLayoutInputNode_h
 
 #include "core/CoreExport.h"
+#include "core/style/ComputedStyle.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
-class ComputedStyle;
 class LayoutObject;
 class NGBreakToken;
 class NGConstraintSpace;
@@ -29,6 +29,8 @@ class CORE_EXPORT NGLayoutInputNode
 
   bool IsBlock() const { return type_ == kLegacyBlock; }
 
+  bool IsFloating() const { return IsBlock() && Style().IsFloating(); }
+
   virtual ~NGLayoutInputNode(){};
 
   // Performs layout on this input node, will return the layout result.