Separate DuplicateFinder from Scanner.

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.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 1425 matching lines @@
     "src/msan.h",
     "src/objects-body-descriptors-inl.h",
     "src/objects-body-descriptors.h",
     "src/objects-debug.cc",
     "src/objects-inl.h",
     "src/objects-printer.cc",
     "src/objects.cc",
     "src/objects.h",
     "src/ostreams.cc",
     "src/ostreams.h",
+    "src/parsing/duplicate-finder.cc",
+    "src/parsing/duplicate-finder.h",
     "src/parsing/expression-classifier.h",
     "src/parsing/func-name-inferrer.cc",
     "src/parsing/func-name-inferrer.h",
     "src/parsing/parameter-initializer-rewriter.cc",
     "src/parsing/parameter-initializer-rewriter.h",
     "src/parsing/parse-info.cc",
     "src/parsing/parse-info.h",
     "src/parsing/parser-base.h",
     "src/parsing/parser.cc",
     "src/parsing/parser.h",
@@ skipping 1117 matching lines @@
 
   deps = [
     ":fuzzer_support",
   ]
 
   configs = [ ":internal_config" ]
 }
 
 v8_fuzzer("wasm_asmjs_fuzzer") {
 }