Implement audio devices and streams HAL delegating to legacy HAL

Changes made to the .hal definition:

  - introduce Effect ID returned by the IEffectsFactory that
    needs to be passed to IStream.{add|remove}Effect; otherwise
    it's impossible to retrieve the underlying HAL effect handle;

  - change "bus address" in DeviceAddress to "string" type;

  - fix signature of some methods w.r.t. returning Result;

  - remove unused "struct AudioPatch".

Bug: 30222631
Test: make
Change-Id: Icb51729ef57bb2a5b0b78609735e7481bc04f95c
diff --git a/audio/common/2.0/default/Android.mk b/audio/common/2.0/default/Android.mk
new file mode 100644
index 0000000..aa60eb2
--- /dev/null
+++ b/audio/common/2.0/default/Android.mk
@@ -0,0 +1,29 @@
+#
+# Copyright (C) 2016 The Android Open Source Project
+#
+# 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.
+
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := android.hardware.audio.common@2.0-util
+LOCAL_SRC_FILES := \
+    EffectMap.cpp \
+
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+
+LOCAL_SHARED_LIBRARIES := \
+    libutils \
+
+include $(BUILD_SHARED_LIBRARY)