Devirtualize Visitor and remove inline visitor specialization.

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

Index: third_party/WebKit/Source/platform/heap/Heap.h
diff --git a/third_party/WebKit/Source/platform/heap/Heap.h b/third_party/WebKit/Source/platform/heap/Heap.h
index c494896d1b5fdc554e716e892a6a87744a4a3729..909da86c9a6b15d03f4b911230e2e1dd9939f71b 100644
--- a/third_party/WebKit/Source/platform/heap/Heap.h
+++ b/third_party/WebKit/Source/platform/heap/Heap.h
@@ -435,6 +435,9 @@ class PLATFORM_EXPORT ThreadHeap {
   // Conservatively checks whether an address is a pointer in any of the
   // thread heaps.  If so marks the object pointed to as live.
   Address checkAndMarkPointer(Visitor*, Address);
+#if DCHECK_IS_ON()
+  Address checkAndMarkPointer(Visitor*, Address, MarkedPointerCallback);
+#endif
 
   size_t objectPayloadSizeForTesting();
 
@@ -692,9 +695,8 @@ Address ThreadHeap::reallocate(void* previous, size_t size) {
   return address;
 }
 
-template <typename Derived>
 template <typename T>
-void VisitorHelper<Derived>::handleWeakCell(Visitor* self, void* object) {
+void Visitor::handleWeakCell(Visitor* self, void* object) {
   T** cell = reinterpret_cast<T**>(object);
   if (*cell && !ObjectAliveTrait<T>::isHeapObjectAlive(*cell))
     *cell = nullptr;
@@ -702,4 +704,6 @@ void VisitorHelper<Derived>::handleWeakCell(Visitor* self, void* object) {
 
 }  // namespace blink
 
+#include "platform/heap/VisitorImpl.h"

[haraken, 2017/01/25 06:14:08]

It looks weird to include a header file at the end of Heap.h...?

[sof, 2017/01/25 06:25:24]

The inlines depend on definitions above, so anywhere else isn't possible. And
we've got a number of places where '#include "Heap.h"' is assumed to get you a
complete definition of "Visitor", including inlines, so that's why it ended up
here.

+
 #endif  // Heap_h