Keep only base/extractor.[cc|h].

plugins/base/build.scons

-# Copyright 2009 Google Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-# ========================================================================
-
-Import('env')
-
-# Build plugin base.
-plugin_base_env = env.Clone()
-# TODO(omaha3): make this configurable for 64-bit support
-plugin_base_env['CCFLAGS'] += ['/D_X86_',]
-plugin_base_env.ComponentLibrary(
-    lib_name='plugin_base',
-    source=[
-      'np_entry.cc',
-      'npn_gate.cc',
-      'npp_gate.cc',
-    ],
-)