!269 定义媒体子系统可配置插件选项

Merge pull request !269 from shihaojun/master

config/subsystem/multimedia/config.gni

+#
+# Copyright (c) 2020 Huawei Device Co., Ltd.
+# 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.
+#
+
+declare_args() {
+  # build histreamer plugin feature ability
+  enable_histreamer_plugin_ffmpeg_adapter = true
+  enable_histreamer_plugin_hdi_adapter = true
+  enable_histreamer_plugin_file_source = true
+  enable_histreamer_plugin_stream_source = true
+}