Add a perf test for BatteryStatsHelper

On Bramble, we get these results:

	endToEnd_median: 321.983605
	getStats_median: 258.134786
	getStats_cached_median: 48.506614
	powerCalculation_median: 51.798291

Test: Lock the device to little cores for consistency
  $ ./frameworks/base/libs/hwui/tests/scripts/prep_generic.sh little
  $ atest BatteryStatsPerfTests

Bug: 173446001

Change-Id: I307bcea38c7001d950de1b506c31b64f89629952
diff --git a/tests/BatteryStatsPerfTest/Android.bp b/tests/BatteryStatsPerfTest/Android.bp
new file mode 100644
index 0000000..58ccec7
--- /dev/null
+++ b/tests/BatteryStatsPerfTest/Android.bp
@@ -0,0 +1,25 @@
+// Copyright (C) 2020 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.
+
+android_test {
+    name: "BatteryStatsPerfTests",
+    srcs: ["src/**/*.java"],
+    static_libs: [
+        "androidx.test.rules",
+        "apct-perftests-utils",
+        "truth-prebuilt",
+    ],
+    platform_apis: true,
+    certificate: "platform",
+}