Remove the global Strength enum class completely.

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 "src/assert-scope.h"
@@ skipping 5606 matching lines @@
       0, kDescriptorIndexBitCount> {};  // NOLINT
   class NumberOfOwnDescriptorsBits: public BitField<int,
       kDescriptorIndexBitCount, kDescriptorIndexBitCount> {};  // NOLINT
   STATIC_ASSERT(kDescriptorIndexBitCount + kDescriptorIndexBitCount == 20);
   class DictionaryMap : public BitField<bool, 20, 1> {};
   class OwnsDescriptors : public BitField<bool, 21, 1> {};
   class HasHiddenPrototype : public BitField<bool, 22, 1> {};
   class Deprecated : public BitField<bool, 23, 1> {};
   class IsUnstable : public BitField<bool, 24, 1> {};
   class IsMigrationTarget : public BitField<bool, 25, 1> {};
-  class IsStrong : public BitField<bool, 26, 1> {};
+  // Bit 26 is free.
   class NewTargetIsBase : public BitField<bool, 27, 1> {};
   // Bit 28 is free.
 
   // Keep this bit field at the very end for better code in
   // Builtins::kJSConstructStubGeneric stub.
   // This counter is used for in-object slack tracking.
   // The in-object slack tracking is considered enabled when the counter is
   // non zero. The counter only has a valid count for initial maps. For
   // transitioned maps only kNoSlackTracking has a meaning, namely that inobject
   // slack tracking already finished for the transition tree. Any other value
@@ skipping 88 matching lines @@
 
   // Tells whether the instance has a call-as-function handler.
   inline void set_is_observed();
   inline bool is_observed();
 
   // Tells whether the instance has a [[Call]] internal method.
   // This property is implemented according to ES6, section 7.2.3.
   inline void set_is_callable();
   inline bool is_callable() const;
 
-  inline void set_is_strong();
-  inline bool is_strong();
   inline void set_new_target_is_base(bool value);
   inline bool new_target_is_base();
   inline void set_is_extensible(bool value);
   inline bool is_extensible();
   inline void set_is_prototype_map(bool value);
   inline bool is_prototype_map() const;
 
   inline void set_elements_kind(ElementsKind elements_kind);
   inline ElementsKind elements_kind();
 
@@ skipping 5130 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_