Refactor embedded pointer visitors for the serializer

src/x64/assembler-x64-inl.h

Index: src/x64/assembler-x64-inl.h
diff --git a/src/x64/assembler-x64-inl.h b/src/x64/assembler-x64-inl.h
index f7b87ec041b079f18d947bb816179b82e4ea018d..ab387d6d0a00c6e326e618b60bdacd97ad947e86 100644
--- a/src/x64/assembler-x64-inl.h
+++ b/src/x64/assembler-x64-inl.h
@@ -224,7 +224,9 @@ Address RelocInfo::target_address() {
 
 
 Address RelocInfo::target_address_address() {
-  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
+                              || rmode_ == EMBEDDED_OBJECT
+                              || rmode_ == EXTERNAL_REFERENCE);
   return reinterpret_cast<Address>(pc_);
 }
 
@@ -399,7 +401,7 @@ void RelocInfo::Visit(ObjectVisitor* visitor) {
   } else if (mode == RelocInfo::GLOBAL_PROPERTY_CELL) {
     visitor->VisitGlobalPropertyCell(this);
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
-    visitor->VisitExternalReference(target_reference_address());
+    visitor->VisitExternalReference(this);
     CPU::FlushICache(pc_, sizeof(Address));
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // TODO(isolates): Get a cached isolate below.
@@ -427,7 +429,7 @@ void RelocInfo::Visit(Heap* heap) {
   } else if (mode == RelocInfo::GLOBAL_PROPERTY_CELL) {
     StaticVisitor::VisitGlobalPropertyCell(heap, this);
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
-    StaticVisitor::VisitExternalReference(target_reference_address());
+    StaticVisitor::VisitExternalReference(this);
     CPU::FlushICache(pc_, sizeof(Address));
 #ifdef ENABLE_DEBUGGER_SUPPORT
   } else if (heap->isolate()->debug()->has_break_points() &&