Do-not-commit: Count layout tree memory usage

third_party/WebKit/Source/core/layout/LayoutFlowThread.h

Index: third_party/WebKit/Source/core/layout/LayoutFlowThread.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutFlowThread.h b/third_party/WebKit/Source/core/layout/LayoutFlowThread.h
index 4bd139fd012263eeb1072d807f52284b1bacd139..0ca2eaf559b8404245e774f93c0be4e1f5f9a49c 100644
--- a/third_party/WebKit/Source/core/layout/LayoutFlowThread.h
+++ b/third_party/WebKit/Source/core/layout/LayoutFlowThread.h
@@ -71,6 +71,8 @@ class CORE_EXPORT LayoutFlowThread : public LayoutBlockFlow {
   virtual bool isLayoutMultiColumnFlowThread() const { return false; }
   virtual bool isLayoutPagedFlowThread() const { return false; }
 
+  char objectSize() const override { return sizeof(this); }
+
   // Search mode when looking for an enclosing fragmentation context.
   enum AncestorSearchConstraint {
     // No constraints. When we're not laying out (but rather e.g. painting or