chromoting: Add JS externs for qunit.

remoting/webapp/build_template.gni

 # Copyright 2015 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.
 
 # Keep in sync with 'remoting_webapp' target in remoting/remoting_client.gypi.
 
 import("//build/config/chrome_build.gni")
 import("//remoting/remoting_locales.gni")
 import("//remoting/remoting_options.gni")
 import("//remoting/remoting_version.gni")
@@ skipping 36 matching lines @@
 }
 
 template("build_webapp_html") {
   target_jscompile = ""
 
   if (enable_remoting_jscompile) {
     target_jscompile = "${target_name}_jscompile"
     target_jscompile_stamp = "$target_gen_dir/${target_jscompile}.stamp"
     action(target_jscompile) {
       js_files = remoting_webapp_js_proto_files + invoker.js_files
+      externs = [
+        remoting_webapp_externs,
+        "../../third_party/closure_compiler/externs/chrome_extensions.js",
+      ]
 
       script = "../../third_party/closure_compiler/compile.py"
       inputs = js_files
       outputs = [
         target_jscompile_stamp,
       ]
 
       args = [
         "--strict",
         "--no-single-file",
         "--externs",
-        "../../third_party/closure_compiler/externs/chrome_extensions.js",
+        externs,
         "--success-stamp",
         rebase_path(target_jscompile_stamp, root_build_dir),
       ]
       args += rebase_path(js_files, root_build_dir)
     }
   }
 
   action(target_name) {
     html_template_file = invoker.html_template_file
     html_template_include_files = invoker.html_template_include_files
@@ skipping 331 matching lines @@
     args += [
       "--manifest_key",
       manifest_key,
     ]
     args += [
       "--app_client_id",
       app_client_id,
     ]
   }
 }