Add default impl of Sensors HAL 2.1

Create a default implementation of HAL 2.1 that shares 90% of the
underlying code with HAL 2.0 since the interfaces are very similar.

Bug: 144139857
Test: compile
Change-Id: Ic6b139df98ddb1f92833b1f2d65e1cecc297fd41
diff --git a/sensors/2.1/default/service.cpp b/sensors/2.1/default/service.cpp
new file mode 100644
index 0000000..1f3087c
--- /dev/null
+++ b/sensors/2.1/default/service.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#define LOG_TAG "android.hardware.sensors@2.1-service"
+
+#include <android/hardware/sensors/2.1/ISensors.h>
+#include <hidl/HidlTransportSupport.h>
+#include <log/log.h>
+#include <utils/StrongPointer.h>
+#include "SensorsV2_1.h"
+
+using android::hardware::configureRpcThreadpool;
+using android::hardware::joinRpcThreadpool;
+using android::hardware::sensors::V2_1::ISensors;
+using android::hardware::sensors::V2_1::implementation::SensorsV2_1;
+
+int main(int /* argc */, char** /* argv */) {
+    configureRpcThreadpool(1, true);
+
+    android::sp<ISensors> sensors = new SensorsV2_1();
+    if (sensors->registerAsService() != ::android::OK) {
+        ALOGE("Failed to register Sensors HAL instance");
+        return -1;
+    }
+
+    joinRpcThreadpool();
+    return 1;  // joinRpcThreadpool shouldn't exit
+}