Move enable extensions define to a build flag.

chrome/chrome_paks.gni

 # Copyright 2016 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/locales.gni")
 import("//chrome/common/features.gni")
+import("//extensions/features/features.gni")
 import("//ui/base/ui_features.gni")
 import("chrome_repack_locales.gni")
 
 # Generates a rule to repack a set of resources, substituting a given string
 # in for the percentage (e.g. "100", "200"). It generates the repacked files in
 # the "gen" directory, and then introduces a copy rule to copy it to the root
 # build directory.
 #
 # Argument:
 #   percent [required]
@@ skipping 234 matching lines @@
       ":${target_name}_locales",
     ]
     if (enable_hidpi) {
       public_deps += [ ":${target_name}_200_percent" ]
     }
     if (defined(invoker.public_deps)) {
       public_deps += invoker.public_deps
     }
   }
 }