StackFrameDepth should be managed per ThreadHeap

third_party/WebKit/Source/platform/heap/Visitor.h

Index: third_party/WebKit/Source/platform/heap/Visitor.h
diff --git a/third_party/WebKit/Source/platform/heap/Visitor.h b/third_party/WebKit/Source/platform/heap/Visitor.h
index 9873523d64c1efc0002dcd7c92b815fccfac82c6..128ad4f51fac5f1cc08bd72ffdc87caeeeeecb32 100644
--- a/third_party/WebKit/Source/platform/heap/Visitor.h
+++ b/third_party/WebKit/Source/platform/heap/Visitor.h
@@ -33,6 +33,7 @@
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/GarbageCollected.h"
+#include "platform/heap/StackFrameDepth.h"
 #include "wtf/Allocator.h"
 #include "wtf/Assertions.h"
 #include "wtf/Forward.h"
@@ -117,7 +118,7 @@ public:
 // VisitorHelper avoids virtual methods by using CRTP.
 // c.f. http://en.wikipedia.org/wiki/Curiously_Recurring_Template_Pattern
 template<typename Derived>
-class VisitorHelper {
+class VisitorHelper : public StackFrameDepth {

[haraken, 2016/09/06 13:03:11]

This looks like a weird class design.

This is okay in this CL but consider making Visitor(Helper) own the
StackFrameDepth.

 public:
     VisitorHelper(ThreadState* state) : m_state(state) { }