Revert of Remove obsolete JSFunction::IsOptimizable predicate.

src/objects.h

 // Copyright 2012 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/allocation.h"
@@ skipping 7570 matching lines @@
 
   // Tells whether this function is defined in an extension script.
   inline bool IsFromExtensionScript();
 
   // Tells whether or not the function needs arguments adaption.
   inline bool NeedsArgumentsAdaption();
 
   // Tells whether or not this function has been optimized.
   inline bool IsOptimized();
 
+  // Tells whether or not this function can be optimized.
+  inline bool IsOptimizable();
+
   // Mark this function for lazy recompilation. The function will be
   // recompiled the next time it is executed.
   void MarkForOptimization();
   void AttemptConcurrentOptimization();
 
   // Tells whether or not the function is already marked for lazy
   // recompilation.
   inline bool IsMarkedForOptimization();
   inline bool IsMarkedForConcurrentOptimization();
 
@@ skipping 3521 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_