When wallpaper colors not ready set sys ui flags when ready

Uses a listener on wallpaper manager to get the wallpaper colors for
fallback home. When the colors are ready it can correctly set the system
ui flags.

Change-Id: I7119c0f035245539cb69bec1ccccecef64d3aff5
Fixes: 79776583
Test: reboot phone, unlock with pin/pattern with light them wallpaper
Test: make RunSettingsRoboTests ROBOTEST_FILTER=FallbackHomeActivityTest

tests/robotests/src/com/android/settings/wallpaper/FallbackHomeActivityTest.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2018 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.wallpaper;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.when;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.app.WallpaperColors;
+import android.app.WallpaperManager;
+import android.app.WallpaperManager.OnColorsChangedListener;
+import android.os.Handler;
+
+import com.android.settings.FallbackHome;
+import com.android.settings.testutils.SettingsRobolectricTestRunner;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.Robolectric;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.android.controller.ActivityController;
+import org.robolectric.annotation.Config;
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+import org.robolectric.shadow.api.Shadow;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Build/Install/Run:
+ *     make RunSettingsRoboTests -j40 ROBOTEST_FILTER=FallbackHomeActivityTest
+ */
+@RunWith(SettingsRobolectricTestRunner.class)
+public class FallbackHomeActivityTest {
+
+    private ActivityController<FallbackHome> mController;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mController = Robolectric.buildActivity(FallbackHome.class);
+    }
+
+    @Test
+    @Config(shadows = ShadowWallpaperManager.class)
+    public void wallpaperColorsChangedListener_ensured_removed() {
+        // onCreate adds the first color listener by WallpaperManager returning null colors
+        ActivityController controller = mController.setup();
+        ShadowWallpaperManager shadowManager = Shadow.extract(RuntimeEnvironment.application
+                .getSystemService(WallpaperManager.class));
+        assertThat(shadowManager.size()).isEqualTo(1);
+
+        // Assert onDestroy will remove the original listener
+        controller.destroy();
+        assertThat(shadowManager.size()).isEqualTo(0);
+    }
+
+    @Implements(WallpaperManager.class)
+    public static class ShadowWallpaperManager {
+
+        private final List<OnColorsChangedListener> mListener = new ArrayList<>();
+
+        public int size() {
+            return mListener.size();
+        }
+
+        @Implementation
+        public boolean isWallpaperServiceEnabled() {
+            return true;
+        }
+
+        @Implementation
+        public @Nullable WallpaperColors getWallpaperColors(int which) {
+            return null;
+        }
+
+        @Implementation
+        public void addOnColorsChangedListener(@NonNull OnColorsChangedListener listener,
+                @NonNull Handler handler) {
+            mListener.add(listener);
+        }
+
+        @Implementation
+        public void removeOnColorsChangedListener(@NonNull OnColorsChangedListener listener) {
+            mListener.remove(listener);
+        }
+    }
+}