NavigationViewUsage saves its state on rotation

Also changes it to use app:menu instead of inflating the menu in Java.

Change-Id: I140fb042c8ea77b5a7c889abf50a1a7926e2dc8b

samples/SupportDesignDemos/res/layout/design_navigation.xml

@@ -40,6 +40,7 @@
                 android:id="@+id/message"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
+                android:freezesText="true"
                 android:gravity="center"
                 android:text="@string/navigation_1"
                 android:textAppearance="?android:attr/textAppearanceLarge"/>
@@ -50,6 +51,7 @@
             android:id="@+id/navigation"
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
-            android:layout_gravity="start"/>
+            android:layout_gravity="start"
+            app:menu="@menu/navigation"/>
 
 </android.support.v4.widget.DrawerLayout>

samples/SupportDesignDemos/src/com/example/android/support/design/widget/NavigationViewUsage.java

@@ -67,7 +67,6 @@ public class NavigationViewUsage extends AppCompatActivity {
 
         // Menu
         NavigationView navigation = (NavigationView) findViewById(R.id.navigation);
-        getMenuInflater().inflate(R.menu.navigation, navigation.getMenu());
         navigation.setNavigationItemSelectedListener(mNavigationItemSelectedListener);
         navigation.inflateHeaderView(R.layout.design_navigation_header);
     }