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/wm/RootWindowContainer.java b/services/core/java/com/android/server/wm/RootWindowContainer.java
index 233e75b..0d6c7e3 100644
--- a/services/core/java/com/android/server/wm/RootWindowContainer.java
+++ b/services/core/java/com/android/server/wm/RootWindowContainer.java
@@ -359,7 +359,7 @@
     }
 
     @Override
-    void onConfigurationChanged(Configuration newParentConfig) {
+    public void onConfigurationChanged(Configuration newParentConfig) {
         prepareFreezingTaskBounds();
         super.onConfigurationChanged(newParentConfig);