Switch WindowContainer to use ConfigurationContainer

To reduce implementation dupication.
This also involved moving ConfigurationContainer to the wm package.

Test: bit FrameworksServicesTests:com.android.server.wm.ConfigurationContainerTests
Test: bit FrameworksServicesTests:com.android.server.wm.WindowContainerTests
Test: go/wm-smoke
Change-Id: Ibeca7e2ad2685f0984fccc66852d53ed9af0925f
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 5f42cdb..590cc7c 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -134,7 +134,6 @@
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
-import android.os.ParcelFileDescriptor;
 import android.os.PowerManager;
 import android.os.Process;
 import android.os.RemoteException;
@@ -167,6 +166,7 @@
 import com.android.internal.widget.LockPatternUtils;
 import com.android.server.LocalServices;
 import com.android.server.am.ActivityStack.ActivityState;
+import com.android.server.wm.ConfigurationContainer;
 import com.android.server.wm.PinnedStackWindowController;
 import com.android.server.wm.WindowManagerService;