Multiwindow config and display size test

Added test to ensure configuration sizes and display
sizes are updated when an Activity is resized.

Bug:28388969

Change-Id: I602aefac2445fe1d7125f83934a8810d1fc85590
diff --git a/hostsidetests/services/activitymanager/app/AndroidManifest.xml b/hostsidetests/services/activitymanager/app/AndroidManifest.xml
index 7ab6e33..48e1634 100755
--- a/hostsidetests/services/activitymanager/app/AndroidManifest.xml
+++ b/hostsidetests/services/activitymanager/app/AndroidManifest.xml
@@ -24,6 +24,11 @@
                 android:resizeableActivity="true"
                 android:exported="true"
         />
+        <activity android:name=".ResizeableActivity"
+                android:resizeableActivity="true"
+                android:exported="true"
+                android:configChanges="orientation|screenSize|smallestScreenSize|screenLayout"
+        />
         <activity android:name=".NonResizeableActivity"
                 android:resizeableActivity="false"
                 android:exported="true"