Make net_unittests_run work with component=shared_library.

net/third_party/nss/ssl_base.isolate

 # 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.
+#
+# This is what is included by base_unittests.
 {
   'conditions': [
     ['OS=="linux" and component=="shared_library" and use_openssl==0', {
       'variables': {
         'isolate_dependency_tracked': [
           '<(PRODUCT_DIR)/lib/libcrssl.so',
         ],
       },
     }],
   ],
 }