I was using the BottomSheetBehavior with the original support library:
implementation 'com.android.support:design:27.1.1' 
When I migrated to use the new androidx libraries though the BottomSheetBehavior is missing. The mapping from the above support library isn't in the AndroidX Refactoring List either, but the migration tool removed it.
What am I missing to include the BottomSheetBehavior with the new androidx libraries.
dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.google.android.material:material:1.0.0-beta01'
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    // ReactiveX
    implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
    implementation 'io.reactivex.rxjava2:rxkotlin:2.2.0'
    implementation 'com.android.support:design:28.1.0'
    // Android Compatability Libraries
    // Version: https://developer.android.com/topic/libraries/support-library/refactor
    implementation 'androidx.appcompat:appcompat:1.0.0-beta01'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-alpha1'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0-beta01'
    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0-beta01'
    implementation 'androidx.recyclerview:recyclerview:1.0.0-beta01'
    // Android Navigation Component
    // Check here for updated version info - will move to androidx soon.
    // https://developer.android.com/topic/libraries/architecture/adding-components
    def nav_version = "1.0.0-alpha04"
    // use -ktx for Kotlin
    implementation "android.arch.navigation:navigation-fragment-ktx:$nav_version"
    implementation "android.arch.navigation:navigation-ui-ktx:$nav_version"
    androidTestImplementation "android.arch.navigation:navigation-testing-ktx:$nav_version"
    // Testing
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.0-alpha4'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha4'
}
 
     
     
     
    