Process weak references between optimized JSFunctions on scavenges.

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
index 7bbd5218b15fce6d55881088a491804b4f421747..2413b67803f090557280955d5196c590287f6007 100644
--- a/src/incremental-marking.cc
+++ b/src/incremental-marking.cc
@@ -830,6 +830,19 @@ void IncrementalMarking::Step(intptr_t allocated_bytes,
         MarkObjectGreyDoNotEnqueue(ctx->normalized_map_cache());
 
         VisitGlobalContext(ctx, &marking_visitor);
+      } else if (map->instance_type() == JS_FUNCTION_TYPE) {
+        marking_visitor.VisitPointers(
+            HeapObject::RawField(obj, JSFunction::kPropertiesOffset),
+            HeapObject::RawField(obj, JSFunction::kCodeEntryOffset));
+
+        marking_visitor.VisitCodeEntry(
+            obj->address() + JSFunction::kCodeEntryOffset);
+
+        marking_visitor.VisitPointers(
+            HeapObject::RawField(obj,
+                                 JSFunction::kCodeEntryOffset + kPointerSize),
+            HeapObject::RawField(obj,
+                                 JSFunction::kNonWeakFieldsEndOffset));
       } else {
         obj->IterateBody(map->instance_type(), size, &marking_visitor);
       }