title: Android application with camera2 library crash on start for SDK19
body: <p>I use androidx.camera.camera2 library in my application. This library for SDK 21 and greater. But i want allow users start application for SDK 19 without camera2 support. I check SDK version in my code, but application crash on start. Can i exclude camera2 from dependencies for old SDK?</p>
  
  <pre><code>05-30 12:13:42.318 2000-2000/com.myapp.android E/AndroidRuntime: FATAL EXCEPTION: main
  Process: com.myapp.android, PID: 2000
  java.lang.NoClassDefFoundError: android.util.Size
      at androidx.camera.camera2.impl.Camera2DeviceSurfaceManager.&lt;clinit&gt;(Camera2DeviceSurfaceManager.java:53)
      at androidx.camera.camera2.Camera2AppConfig.create(Camera2AppConfig.java:58)
      at androidx.camera.camera2.impl.Camera2Initializer.onCreate(Camera2Initializer.java:44)
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1591)
      at android.content.ContentProvider.attachInfo(ContentProvider.java:1562)
      at android.app.ActivityThread.installProvider(ActivityThread.java:4790)
      at android.app.ActivityThread.installContentProviders(ActivityThread.java:4385)
      at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4325)
      at android.app.ActivityThread.access$1500(ActivityThread.java:135)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
      at android.os.Handler.dispatchMessage(Handler.java:102)
      at android.os.Looper.loop(Looper.java:136)
      at android.app.ActivityThread.main(ActivityThread.java:5017)
      at java.lang.reflect.Method.invokeNative(Native Method)
      at java.lang.reflect.Method.invoke(Method.java:515)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
      at dalvik.system.NativeStart.main(Native Method)
  </code></pre>