[WIP] JSForInLowering and JSForInHasOwnProperty.

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 1180 matching lines @@
     "src/compiler/int64-lowering.cc",
     "src/compiler/int64-lowering.h",
     "src/compiler/js-builtin-reducer.cc",
     "src/compiler/js-builtin-reducer.h",
     "src/compiler/js-call-reducer.cc",
     "src/compiler/js-call-reducer.h",
     "src/compiler/js-context-specialization.cc",
     "src/compiler/js-context-specialization.h",
     "src/compiler/js-create-lowering.cc",
     "src/compiler/js-create-lowering.h",
+    "src/compiler/js-for-in-lowering.cc",
+    "src/compiler/js-for-in-lowering.h",
     "src/compiler/js-frame-specialization.cc",
     "src/compiler/js-frame-specialization.h",
     "src/compiler/js-generic-lowering.cc",
     "src/compiler/js-generic-lowering.h",
     "src/compiler/js-graph.cc",
     "src/compiler/js-graph.h",
     "src/compiler/js-inlining-heuristic.cc",
     "src/compiler/js-inlining-heuristic.h",
     "src/compiler/js-inlining.cc",
     "src/compiler/js-inlining.h",
@@ skipping 1973 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_compile_fuzzer") {
 }