Add new action bar demos:

- Buttons for showing/hiding action bar and system UI
  in the basic action bar demo.
- New system UI demo that uses a non-overlay action bar.

Change-Id: Id3fbaa77365476489c558a2a43855a01f383551c

samples/ApiDemos/src/com/example/android/apis/view/SystemUIModes.java

@@ -166,8 +166,6 @@ public class SystemUIModes extends Activity
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
-
         setContentView(R.layout.system_ui_modes);
         mImage = (IV) findViewById(R.id.image);
         mImage.setActivity(this);

samples/ApiDemos/src/com/example/android/apis/view/SystemUIModesOverlay.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.apis.view;
+
+import android.os.Bundle;
+import android.view.Window;
+
+/**
+ * Version of demo that uses the action bar in overlay mode.
+ */
+public class SystemUIModesOverlay extends SystemUIModes {
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
+        super.onCreate(savedInstanceState);
+    }
+}