Revert commit 14524, which builds NSS and NSPR libraries, for secure networking.

runtime/tools/gyp/nss_configurations.gypi

-# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-# for details. All rights reserved. Use of this source code is governed by a
-# BSD-style license that can be found in the LICENSE file.
-
-# This file is included to modify the configurations to build third-party
-# code from Mozilla's NSS and NSPR libraries, modified by the Chromium project.
-# This code is C code, not C++, and is not warning-free, so we need to remove
-# C++-specific flags, and add flags to supress the warnings in the code.
-# This file is included from gyp files in the runtime/bin/net directory.
-{
-  'variables': {
-    # Used by third_party/nss, which is from Chromium.
-    'os_posix': 1,
-    'os_bsd': 0,
-    'chromeos': 0,
-    'clang': 0,
-  },
-  'target_defaults': {
-    'cflags': [
-      '-Wno-unused-variable',
-      '-Wno-unused-but-set-variable',
-      '-Wno-missing-field-initializers',
-      '-Wno-uninitialized',
-      '-Wno-sign-compare',
-      '-Wno-empty-body',
-      '-Wno-type-limits',
-      '-Wno-pointer-to-int-cast',
-      '-UHAVE_CVAR_BUILT_ON_SEM',
-    ],
-    # Removes these flags from the list cflags.
-    'cflags!': [
-      # NSS code from upstream mozilla builds with warnings,
-      # so we must allow warnings without failing.
-      '-Werror',
-      '-Wall',
-      '-ansi',
-      # Not supported for C, only for C++.
-      '-Wnon-virtual-dtor',
-      '-Wno-conversion-null',
-      '-fno-rtti',
-      '-fvisibility-inlines-hidden',
-      '-Woverloaded-virtual',
-    ],
-    'configurations': {
-      'Dart_Base': {
-        'xcode_settings': {
-          'WARNING_CFLAGS!': [
-            '-Wall',
-            '-Wextra',
-          ],
-        },
-      },
-      # Dart_Debug and Dart_Release are merged after Dart_Base, so we can
-      # override the 'ansi' and '-Werror' flags set at the global level in
-      # tools/gyp/configurations_xcode.gypi.
-      'Dart_Debug': {
-        'xcode_settings': {
-          # Remove 'ansi' setting.
-          'GCC_C_LANGUAGE_STANDARD': 'c99',
-          'GCC_TREAT_WARNINGS_AS_ERRORS': 'NO', # -Werror off
-        },
-      },
-      'Dart_Release': {
-        'xcode_settings': {
-          # Remove 'ansi' setting.
-          'GCC_C_LANGUAGE_STANDARD': 'c99',
-          'GCC_TREAT_WARNINGS_AS_ERRORS': 'NO', # -Werror off
-        },
-      },
-    },
-  },
-}