[layoutng] Implement state machine for async layout

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

Index: third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.h b/third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.h
index fdff8977381d66ea5e8d1bcc8f436373494e289f..e8547c38f95a272fe85aa526760f036b76a8f955 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.h
@@ -15,12 +15,13 @@ class NGConstraintSpace;
 class NGFragment;
 
 // Base class for all LayoutNG algorithms.
-class CORE_EXPORT NGLayoutAlgorithm {
+class CORE_EXPORT NGLayoutAlgorithm
+    : public GarbageCollectedFinalized<NGLayoutAlgorithm> {
   WTF_MAKE_NONCOPYABLE(NGLayoutAlgorithm);
-  USING_FAST_MALLOC(NGLayoutAlgorithm);
 
  public:
   NGLayoutAlgorithm() {}
+  virtual ~NGLayoutAlgorithm() {}
 
   // Actual layout function. Lays out the children and descendents within the
   // constraints given by the NGConstraintSpace. Returns a fragment with the
@@ -33,6 +34,8 @@ class CORE_EXPORT NGLayoutAlgorithm {
   // TODO(layout-ng): Should we have a StartLayout function to avoid passing
   // the same space for each Layout iteration?
   virtual bool Layout(const NGConstraintSpace*, NGFragment**) = 0;
+
+  DEFINE_INLINE_VIRTUAL_TRACE() {}
 };
 
 }  // namespace blink