Enable NPAPI if policy has plugin policies.

chrome/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("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 
 # //build/config/android/rules.gni imports //tools/grit/grit_rule.gni, which
 # produces a conflict for the "grit" template so we have to only include one.
@@ skipping 368 matching lines @@
       sources += rebase_path(
               gypi_values.chrome_browser_policy_shared_with_ios_not_chromeos_sources,
               ".",
               "//chrome")
     }
     if (is_win || is_mac || is_desktop_linux) {
       sources += rebase_path(gypi_values.chrome_browser_policy_desktop_sources,
                              ".",
                              "//chrome")
     }
+    if (enable_plugins) {
+      sources += rebase_path(gypi_values.chrome_browser_policy_plugin_sources,
+                             ".",
+                             "//chrome")
+    }
     if (is_android || is_ios) {
       sources += rebase_path(gypi_values.chrome_browser_policy_mobile_sources,
                              ".",
                              "//chrome")
     } else {
       deps += [
         "//chrome/browser/policy:path_parser",
         "//net:net_browser_services",
       ]
     }
@@ skipping 715 matching lines @@
     ]
   }
 
   if (enable_wifi_bootstrapping) {
     sources += [
       "local_discovery/wifi/mock_wifi_manager.cc",
       "local_discovery/wifi/mock_wifi_manager.h",
     ]
   }
 }