GN: Remove "outputs" parameter for java_cpp_enum()

components/offline_pages/BUILD.gn

 # 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.
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 # GYP: //components/offline_pages.gypi:offline_pages
 static_library("offline_pages") {
@@ skipping 36 matching lines @@
     "//components/offline_pages/proto:offline_pages_proto",
     "//testing/gtest",
   ]
 }
 
 if (is_android) {
   java_cpp_enum("offline_pages_enums_java") {
     sources = [
       "offline_page_model.h",
     ]
-    outputs = [
-      "org/chromium/components/offlinepages/DeletePageResult.java",
-      "org/chromium/components/offlinepages/SavePageResult.java",
-    ]
   }
 }