[heap] Only visit strong links during scavenge of promoted objects

src/objects.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 8544 matching lines @@
   static const int kPrototypeOrInitialMapOffset = JSObject::kHeaderSize;
   static const int kSharedFunctionInfoOffset =
       kPrototypeOrInitialMapOffset + kPointerSize;
   static const int kContextOffset = kSharedFunctionInfoOffset + kPointerSize;
   static const int kLiteralsOffset = kContextOffset + kPointerSize;
   static const int kNonWeakFieldsEndOffset = kLiteralsOffset + kPointerSize;
   static const int kCodeEntryOffset = kNonWeakFieldsEndOffset;
   static const int kNextFunctionLinkOffset = kCodeEntryOffset + kPointerSize;
   static const int kSize = kNextFunctionLinkOffset + kPointerSize;
 
+  typedef FixedBodyDescriptor<kNextFunctionLinkOffset, kSize, kSize>
+      BodyDescriptorWeakFields;
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSFunction);
 };
 
 
 // JSGlobalProxy's prototype must be a JSGlobalObject or null,
 // and the prototype is hidden. JSGlobalProxy always delegates
 // property accesses to its prototype if the prototype is not null.
 //
 // A JSGlobalProxy can be reinitialized which will preserve its identity.
@@ skipping 3289 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_