[about-omnibox] formatting omnibox.js

Where appropriate, replaced `var`s with `let`s, `function`s with lambdas, closure function with braces, and construction functions with classes.

Change-Id: I45dcf2e7aa840242cf2b25cd73cf8a81bfe5b3da
Reviewed-on: https://chromium-review.googlesource.com/1239352
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593684}

chrome/browser/resources/BUILD.gn

@@ -22,6 +22,7 @@ if (closure_compile) {
         "md_history:closure_compile",
         "media_router:closure_compile",
         "ntp4:closure_compile",
+        "omnibox:closure_compile",
         "pdf:closure_compile",
         "print_preview:closure_compile",
         "settings:closure_compile",

chrome/browser/resources/omnibox/.eslintrc.js

+// Copyright 2018 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.
+
+module.exports = {
+  'env': {
+    'browser': true,
+    'es6': true,
+  },
+  'rules': {
+    'no-var': 'error',
+  },
+};

chrome/browser/resources/omnibox/BUILD.gn

+# Copyright 2018 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("//third_party/closure_compiler/compile_js.gni")
+
+js_type_check("closure_compile") {
+  deps = [
+    ":omnibox",
+  ]
+}
+
+js_library("omnibox") {
+  deps = [
+    "//ui/webui/resources/js:util",
+  ]
+  extra_deps = [ "//chrome/browser/ui/webui/omnibox:mojo_bindings_js" ]
+  externs_list = [
+    "$root_gen_dir/chrome/browser/ui/webui/omnibox/omnibox.mojom.externs.js",
+    "$externs_path/mojo.js",
+  ]
+}