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

src/objects-inl.h

 // Copyright 2006-2008 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 2343 matching lines @@
               kStartPositionAndTypeOffset)
 INT_ACCESSORS(SharedFunctionInfo, end_position, kEndPositionOffset)
 INT_ACCESSORS(SharedFunctionInfo, function_token_position,
               kFunctionTokenPositionOffset)
 INT_ACCESSORS(SharedFunctionInfo, compiler_hints,
               kCompilerHintsOffset)
 INT_ACCESSORS(SharedFunctionInfo, this_property_assignments_count,
               kThisPropertyAssignmentsCountOffset)
 
 
+bool Script::HasValidSource() {
+  Object* src = this->source();
+  if (!src->IsString()) return true;
+  String* src_str = String::cast(src);
+  if (!StringShape(src_str).IsExternal()) return true;
+  if (src_str->IsAsciiRepresentation()) {
+    return ExternalAsciiString::cast(src)->resource() != NULL;
+  } else if (src_str->IsTwoByteRepresentation()) {
+    return ExternalTwoByteString::cast(src)->resource() != NULL;
+  }
+  return true;
+}
+
+
 void SharedFunctionInfo::DontAdaptArguments() {
   ASSERT(code()->kind() == Code::BUILTIN);
   set_formal_parameter_count(kDontAdaptArgumentsSentinel);
 }
 
 
 int SharedFunctionInfo::start_position() {
   return start_position_and_type() >> kStartPositionShift;
 }
 
@@ skipping 504 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_