Fix a crash in Logger::LogCompiledFunctions due to a presence of scripts with disposed source.

src/objects.h

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2980 matching lines @@
   // [eval_from_function]: for eval scripts the funcion from which eval was
   // called.
   DECL_ACCESSORS(eval_from_function, Object)
 
   // [eval_from_instructions_offset]: the instruction offset in the code for the
   // function from which eval was called where eval was called.
   DECL_ACCESSORS(eval_from_instructions_offset, Smi)
 
   static inline Script* cast(Object* obj);
 
+  // If script source is an external string, check that the underlying
+  // resource is accessible. Otherwise, always return true.
+  inline bool HasValidSource();
+
 #ifdef DEBUG
   void ScriptPrint();
   void ScriptVerify();
 #endif
 
   static const int kSourceOffset = HeapObject::kHeaderSize;
   static const int kNameOffset = kSourceOffset + kPointerSize;
   static const int kLineOffsetOffset = kNameOffset + kPointerSize;
   static const int kColumnOffsetOffset = kLineOffsetOffset + kPointerSize;
   static const int kDataOffset = kColumnOffsetOffset + kPointerSize;
@@ skipping 1869 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_