Remove harmony-strings flag.

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/mips.gni")
 
 # Because standalone V8 builds are not supported, assume this is part of a
 # Chromium build.
@@ skipping 241 matching lines @@
   script = "tools/js2c.py"
 
   # The script depends on this other script, this rule causes a rebuild if it
   # changes.
   inputs = [ "tools/jsmin.py" ]
 
   sources = [
     "src/macros.py",
     "src/proxy.js",
     "src/generator.js",
-    "src/harmony-string.js",
     "src/harmony-array.js",
     "src/harmony-array-includes.js",
     "src/harmony-typedarray.js",
     "src/harmony-tostring.js",
     "src/harmony-templates.js",
     "src/harmony-regexp.js",
     "src/harmony-reflect.js"
   ]
 
   outputs = [
@@ skipping 1318 matching lines @@
       sources += [
         "src/d8-debug.cc",
         "$target_gen_dir/d8-js.cc",
       ]
     }
     if (v8_enable_i18n_support) {
       deps += [ "//third_party/icu" ]
     }
   }
 }