Add BUILD.gn file for components's translate_common target.

tools/gn/secondary/BUILD.gn

 # Copyright (c) 2013 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.
 
 gyp_file = "root.gyp"
 external = true
 
 group("root") {
   deps = [
     "//base(//build/toolchain/nacl:x86_newlib)",
     "//chrome",
     "//components/navigation_metrics",
     "//components/onc:onc_component",
     "//components/startup_metric_utils",
+    "//components/translate:translate_common",
     "//crypto",
     "//device/usb:device_usb",
     "//ipc",
     "//net",
     "//net/third_party/nss:ssl",
     "//sdch",
     "//third_party/icu:icudata",
     "//third_party/leveldatabase",
     "//third_party/zlib",
     "//third_party/WebKit/Source/weborigin",
     "//skia",
     "//tools/gn",
     "//url",
   ]
 }