title: Few memory leaks in Facebook SDK
body: <p>I tried to make social module for my app, something like wrapper, that will contain Google+,Facebook and twitter integration templates.</p>
  <p>Now I am working with Facebook SDK and decided to use LeakCanary in my app, after successful log in I rotated the device few times, and see the following information:</p>
  <p><a href="https://i.stack.imgur.com/O0lVT.png" rel="noreferrer"><img src="https://i.stack.imgur.com/O0lVT.png" alt="enter image description here" /></a></p>
  <p>Here is MainActivity.class:</p>
  <pre><code>public class MainActivity extends AppCompatActivity {
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      ButterKnife.bind(this);
      setFragment();
  
  }
  private void setFragment(){
      getSupportFragmentManager()
              .beginTransaction()
              .add(R.id.container, new MainFragment())
              .commit();
  }
  }
  </code></pre>
  <p>Here is how I log in to Facebook:</p>
  <pre><code> public void configureFacebook(@NonNull Fragment fragment,
                                @Nullable String permissions, @Nullable String requestFields) {
      setPermissionAndRequestFields(permissions, requestFields);
      loginManager = LoginManager.getInstance();
      callbackManager = CallbackManager.Factory.create();
      loginManager.registerCallback(callbackManager, facebookCallback);
      loginManager.logInWithReadPermissions(fragment, Arrays.asList(this.permissions));
      loginManager=null;
  
  }
  </code></pre>
  <p>I tried log in using Login Button too, in this case I catch this issue and new one, with following info:</p>
  <p><a href="https://i.stack.imgur.com/sRMO0.png" rel="noreferrer"><img src="https://i.stack.imgur.com/sRMO0.png" alt="enter image description here" /></a></p>
  <p>Here is how I log in using LoginButton.class:</p>
  <pre><code>  public void configureFacebook(@NonNull Fragment fragment,
                                @Nullable String permissions, @Nullable String requestFields, @NonNull LoginButton button) {
      callbackManager = CallbackManager.Factory.create();
      setFbButton(button);
      setPermissionAndRequestFields(permissions, requestFields);
      fbButton.setFragment(fragment);
      fbButton.setReadPermissions(this.permissions);
      fbButton.registerCallback(callbackManager, facebookCallback);
  
  }
  </code></pre>
  <p>I can't figure out how to fix those issues. What I am doing wrong?</p>
  <p>UPDATE: Leak in Facebook Activity.class has been shown without the rotation device.</p>