StackFrameDepth should be managed per ThreadHeap

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

Index: third_party/WebKit/Source/platform/heap/TraceTraits.h
diff --git a/third_party/WebKit/Source/platform/heap/TraceTraits.h b/third_party/WebKit/Source/platform/heap/TraceTraits.h
index 5bae4425f4752d695cf3d0e2f8f3d91ccd1325b1..a79223fccff718e7b6cc0375a326c9b5e3dce50a 100644
--- a/third_party/WebKit/Source/platform/heap/TraceTraits.h
+++ b/third_party/WebKit/Source/platform/heap/TraceTraits.h
@@ -70,8 +70,8 @@ public:
             // but test and appropriately handle them should they occur
             // in release builds.
             //
-            ASSERT(StackFrameDepth::isAcceptableStackUse());
-            if (LIKELY(StackFrameDepth::isSafeToRecurse())) {
+            DCHECK(visitor->heap().stackFrameDepth().isAcceptableStackUse());
+            if (LIKELY(visitor->heap().stackFrameDepth().isSafeToRecurse())) {

[haraken, 2016/09/02 09:07:57]

I hope this won't regress performance.

Moving StackFrameDepthScope to Visitor might help the compiler to generate more
optimized code.

                 if (visitor->ensureMarked(t)) {
                     TraceTrait<T>::trace(visitor, const_cast<T*>(t));
                 }