GN files for running Closure Compiler

chrome/browser/resources/chromeos/braille_ime/BUILD.gn

Index: chrome/browser/resources/chromeos/braille_ime/BUILD.gn
diff --git a/chrome/browser/resources/chromeos/braille_ime/BUILD.gn b/chrome/browser/resources/chromeos/braille_ime/BUILD.gn
index 092cbce3bc1a7d61cb869c4cb6f49362ef09dd05..2983ae002429bd62765f0291597061301f8e1ba4 100644
--- a/chrome/browser/resources/chromeos/braille_ime/BUILD.gn
+++ b/chrome/browser/resources/chromeos/braille_ime/BUILD.gn
@@ -2,9 +2,11 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-assert(is_chromeos)
+import("//third_party/closure_compiler/compile_js2.gni")
 
 copy("braille_ime_manifest") {
+  assert(is_chromeos)
+
   sources = [
     "manifest.json",
   ]
@@ -12,3 +14,9 @@ copy("braille_ime_manifest") {
     "$root_out_dir/resources/chromeos/braille_ime/manifest.json",
   ]
 }
+
+compile_js("compile_externs") {
+  sources = [
+    "externs.js",
+  ]
+}