Remove dead code from LookupResult

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # TODO(jochen): These will need to be user-settable to support standalone V8
 # builds.
 v8_compress_startup_data = "off"
 v8_deprecation_warnings = false
 v8_enable_disassembler = false
 v8_enable_gdbjit = false
@@ skipping 588 matching lines @@
     "src/extensions/gc-extension.h",
     "src/extensions/statistics-extension.cc",
     "src/extensions/statistics-extension.h",
     "src/extensions/trigger-failure-extension.cc",
     "src/extensions/trigger-failure-extension.h",
     "src/factory.cc",
     "src/factory.h",
     "src/fast-dtoa.cc",
     "src/fast-dtoa.h",
     "src/feedback-slots.h",
-    "src/field-index.cc",
     "src/field-index.h",
     "src/field-index-inl.h",
     "src/fixed-dtoa.cc",
     "src/fixed-dtoa.h",
     "src/flag-definitions.h",
     "src/flags.cc",
     "src/flags.h",
     "src/frames-inl.h",
     "src/frames.cc",
     "src/frames.h",
@@ skipping 722 matching lines @@
     deps = [
       ":v8_base",
       ":v8_nosnapshot",
     ]
   }
 
   direct_dependent_configs = [ ":external_config" ]
 }
 
 }