Disable the control of draw over permission for SystemUI

Bug: 31077838
Test: make SettingsTests && adb install -r \
${OUT}/data/app/SettingsTests/SettingsTests.apk \
&& adb shell am instrument -w  \
'com.android.settings.tests/android.support.test.runner.AndroidJUnitRunner'

Change-Id: I760590f5558f2d686ffbfe78234a8b08e13883fd

src/com/android/settings/applications/AppStateOverlayBridge.java

@@ -23,6 +23,9 @@ import com.android.settingslib.applications.ApplicationsState;
 import com.android.settingslib.applications.ApplicationsState.AppEntry;
 import com.android.settingslib.applications.ApplicationsState.AppFilter;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /*
  * Connects info of apps that draw overlay to the ApplicationsState. Wraps around the generic
  * AppStateAppOpsBridge class to tailor to the semantics of SYSTEM_ALERT_WINDOW. Also provides app
@@ -62,6 +65,13 @@ public class AppStateOverlayBridge extends AppStateAppOpsBridge {
     }
 
     public static class OverlayState extends AppStateAppOpsBridge.PermissionState {
+        public final boolean controlEnabled;
+
+        private static final List<String> DISABLE_PACKAGE_LIST = new ArrayList<>();
+
+        static {
+            DISABLE_PACKAGE_LIST.add("com.android.systemui");
+        }
 
         public OverlayState(PermissionState permissionState) {
             super(permissionState.packageName, permissionState.userHandle);
@@ -69,6 +79,7 @@ public class AppStateOverlayBridge extends AppStateAppOpsBridge {
             this.appOpMode = permissionState.appOpMode;
             this.permissionDeclared = permissionState.permissionDeclared;
             this.staticPermissionGranted = permissionState.staticPermissionGranted;
+            controlEnabled = !DISABLE_PACKAGE_LIST.contains(permissionState.packageName);
         }
     }
 

src/com/android/settings/applications/DrawOverlayDetails.java

@@ -144,7 +144,7 @@ public class DrawOverlayDetails extends AppInfoWithHeader implements OnPreferenc
         boolean isAllowed = mOverlayState.isPermissible();
         mSwitchPref.setChecked(isAllowed);
         // you cannot ask a user to grant you a permission you did not have!
-        mSwitchPref.setEnabled(mOverlayState.permissionDeclared);
+        mSwitchPref.setEnabled(mOverlayState.permissionDeclared && mOverlayState.controlEnabled);
         mOverlayPrefs.setEnabled(isAllowed);
         getPreferenceScreen().removePreference(mOverlayPrefs);
 

tests/app/src/com/android/settings/tests/DrawOverlayDetailsTest.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2016 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.android.settings.tests;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.support.test.InstrumentationRegistry;
+import org.junit.runner.RunWith;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+import org.junit.Test;
+import com.android.settings.R;
+
+import static android.support.test.espresso.Espresso.onView;
+import static android.support.test.espresso.action.ViewActions.click;
+import static android.support.test.espresso.assertion.ViewAssertions.matches;
+import static android.support.test.espresso.matcher.ViewMatchers.isEnabled;
+import static android.support.test.espresso.matcher.ViewMatchers.withText;
+import static org.hamcrest.core.IsNot.not;
+import static android.support.test.espresso.Espresso.openActionBarOverflowOrOptionsMenu;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class DrawOverlayDetailsTest {
+    private final static String PACKAGE_SYSTEM_UI = "com.android.systemui";
+
+    @Test
+    public void testSystemUiDrawOverlayDetails_Disabled() throws Exception{
+        Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
+        instrumentation.startActivitySync(new Intent(android.provider.Settings
+                .ACTION_MANAGE_OVERLAY_PERMISSION));
+
+        final Context targetContext = instrumentation.getTargetContext();
+
+        final PackageManager packageManager = targetContext.getPackageManager();
+        final String appName = (String) packageManager.getApplicationLabel(packageManager
+                .getApplicationInfo(PACKAGE_SYSTEM_UI, PackageManager.GET_META_DATA));
+
+        openActionBarOverflowOrOptionsMenu(targetContext);
+        onView(withText(targetContext.getString(R.string.menu_show_system))).perform(click());
+        onView(withText(appName)).perform(click());
+        onView(withText(targetContext.getString(R.string.permit_draw_overlay))).check(matches
+                (not(isEnabled())));
+    }
+
+}