Add a BUILD file with mobile harness target to playbacktests/src/androidTest folder

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=145267137

playbacktests/src/androidTest/AndroidManifest.xml

-<?xml version="1.0" encoding="utf-8"?>
-<!-- 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.
--->
-
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
-    package="com.google.android.exoplayer2.playbacktests">
-
-  <uses-permission android:name="android.permission.INTERNET"/>
-  <uses-permission android:name="android.permission.WAKE_LOCK"/>
-
-  <uses-sdk android:minSdkVersion="9" android:targetSdkVersion="24"/>
-
-  <application android:debuggable="true"
-      android:allowBackup="false"
-      tools:ignore="MissingApplicationIcon,HardcodedDebugMode">
-    <uses-library android:name="android.test.runner"/>
-
-    <activity android:name="com.google.android.exoplayer2.playbacktests.util.HostActivity"
-        android:configChanges="keyboardHidden|orientation|screenSize"
-        android:label="ExoPlayerTest"/>
-
-  </application>
-
-  <instrumentation
-      android:targetPackage="com.google.android.exoplayer2.playbacktests"
-      android:name="android.test.InstrumentationTestRunner"
-      tools:replace="android:targetPackage"/>
-
-</manifest>