Convert enable_plugins to a buildflag header.

components/autofill/content/browser/BUILD.gn

 # Copyright 2014 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/protobuf/proto_library.gni")
 
 static_library("browser") {
   sources = [
     "content_autofill_driver.cc",
     "content_autofill_driver.h",
@@ skipping 19 matching lines @@
     "//components/strings",
     "//components/user_prefs",
     "//components/webdata/common",
     "//content/public/browser",
     "//content/public/common",
     "//device/geolocation",
     "//google_apis",
     "//gpu/config",
     "//mojo/common:common_base",
     "//net",
+    "//ppapi/features",
     "//services/service_manager/public/cpp",
     "//sql",
     "//third_party/icu",
     "//third_party/libphonenumber",
     "//ui/base",
     "//ui/display",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//url",
   ]
@@ skipping 26 matching lines @@
     "//google_apis",
     "//google_apis:test_support",
     "//mojo/common:common_base",
     "//net",
     "//net:test_support",
     "//services/service_manager/public/cpp",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }