问什么是AppMeasurementService ?为什么Android Studio要在我的应用程序中添加这项服务？

EN

com.google.android.c2dmpermission.RECEIVE
android.permission.USE_CREDENTIALS

  build\intermediates\manifests\full\release 

    <!-- Include the AdActivity and InAppPurchaseActivity configChanges and themes. -->
    <activity
        android:name="com.google.android.gms.ads.AdActivity"
        android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"
        android:theme="@android:style/Theme.Translucent" />
    <activity
        android:name="com.google.android.gms.ads.purchase.InAppPurchaseActivity"
        android:theme="@style/Theme.IAPTheme" />

    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />

    <provider
        android:name="com.google.android.gms.measurement.AppMeasurementContentProvider"
        android:authorities="net.stefano.stefanoface.google_measurement_service"
        android:exported="false" />

    <receiver
        android:name="com.google.android.gms.measurement.AppMeasurementReceiver"
        android:enabled="true" >
        <intent-filter>
            <action android:name="com.google.android.gms.measurement.UPLOAD" />
        </intent-filter>
    </receiver>

    <service
        android:name="com.google.android.gms.measurement.AppMeasurementService"
        android:enabled="true"
        android:exported="false" />

    <meta-data
        android:name="com.google.android.wearable.beta.app"
        android:resource="@xml/android_wear_micro_apk" />

     compileSdkVersion 22
     buildToolsVersion "22.0.1"
    defaultConfig {
        applicationId "net.stefano.stefanoface"
        minSdkVersion 18
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    wearApp project(':wear')
    compile 'com.android.support:appcompat-v7:22.2.1'
    compile 'com.google.android.gms:play-services:8.1.0'
    compile 'com.android.support:design:22.2.1'
    compile 'com.google.android.gms:play-services-base:7.5.0'
}