Add a GN flag for the Windows multi-dll build.

third_party/widevine/cdm/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/chrome_build.gni")
 import("//build/config/features.gni")
 import("//chrome/version.gni")  # TODO layering violation
 import("//media/cdm/ppapi/cdm_adapter.gni")
 import("//third_party/widevine/cdm/widevine.gni")
 
 widevine_arch = current_cpu
 if (widevine_arch == "x86") {
   widevine_arch = "ia32"
 }
 
@@ skipping 139 matching lines @@
 # on the license server.
 source_set("widevine_test_license_server") {
   if (is_chrome_branded && is_linux) {
     deps = [
       # TODO(jrummell)
       # This target should be removed and targets should have datadeps on this target:
       #"//third_party/widevine/test/license_server/license_server.gyp:test_license_server"
     ]
   }
 }