Check device for config_enableWallpaperService before calling service.

On some devices, it is possible that config_enableWallpaperService is
false, in which then there is no wallpaper service on device. Calling
WallpaperManager#getWallpaperId will then result in an NPE. We should
just do a check and return false.

Bug: 62387789
Test: RoboSettingsTest
Change-Id: I31db6845f06533d92140bf91d0f7fc7e7bedc5c5
diff --git a/src/com/android/settings/wallpaper/WallpaperSuggestionActivity.java b/src/com/android/settings/wallpaper/WallpaperSuggestionActivity.java
index 77142ed..8d798b1 100644
--- a/src/com/android/settings/wallpaper/WallpaperSuggestionActivity.java
+++ b/src/com/android/settings/wallpaper/WallpaperSuggestionActivity.java
@@ -59,7 +59,8 @@
     @VisibleForTesting
     public static boolean isSuggestionComplete(Context context) {
         final WallpaperManagerWrapper manager = new WallpaperManagerWrapper(context);
-        return manager.getWallpaperId(WallpaperManager.FLAG_SYSTEM) > 0;
+        return manager.isWallpaperServiceEnabled() ? manager.getWallpaperId(
+                WallpaperManager.FLAG_SYSTEM) > 0 : false;
     }
 
 }
diff --git a/src/com/android/settings/wrapper/WallpaperManagerWrapper.java b/src/com/android/settings/wrapper/WallpaperManagerWrapper.java
index 89015e5..eabc5bb 100644
--- a/src/com/android/settings/wrapper/WallpaperManagerWrapper.java
+++ b/src/com/android/settings/wrapper/WallpaperManagerWrapper.java
@@ -22,12 +22,23 @@
 public class WallpaperManagerWrapper {
 
     private final WallpaperManager mWallpaperManager;
+    private final boolean mWallpaperServiceEnabled;
 
     public WallpaperManagerWrapper(Context context) {
-        mWallpaperManager = (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE);
+        mWallpaperServiceEnabled = context.getResources().getBoolean(
+                com.android.internal.R.bool.config_enableWallpaperService);
+        mWallpaperManager = mWallpaperServiceEnabled ? (WallpaperManager) context.getSystemService(
+                Context.WALLPAPER_SERVICE) : null;
+    }
+
+    public boolean isWallpaperServiceEnabled() {
+        return mWallpaperServiceEnabled;
     }
 
     public int getWallpaperId(int which) {
+        if (!mWallpaperServiceEnabled) {
+            throw new RuntimeException("This device does not have wallpaper service enabled.");
+        }
         return mWallpaperManager.getWallpaperId(which);
     }
 }
diff --git a/tests/robotests/src/com/android/settings/wallpaper/WallpaperSuggestionActivityTest.java b/tests/robotests/src/com/android/settings/wallpaper/WallpaperSuggestionActivityTest.java
index ced4b0a..daaf4b3 100644
--- a/tests/robotests/src/com/android/settings/wallpaper/WallpaperSuggestionActivityTest.java
+++ b/tests/robotests/src/com/android/settings/wallpaper/WallpaperSuggestionActivityTest.java
@@ -17,12 +17,14 @@
 package com.android.settings.wallpaper;
 
 import static com.google.common.truth.Truth.assertThat;
+
 import static org.mockito.Mockito.when;
 import static org.robolectric.Shadows.shadowOf;
 
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.content.res.Resources;
 
 import com.android.settings.SubSettings;
 import com.android.settings.TestConfig;
@@ -42,16 +44,16 @@
 import org.robolectric.shadows.ShadowActivity;
 
 @RunWith(SettingsRobolectricTestRunner.class)
-@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION,
-        shadows = {
-                WallpaperSuggestionActivityTest.ShadowWallpaperManagerWrapper.class
-        })
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
 public class WallpaperSuggestionActivityTest {
 
     @Mock
     private Context mContext;
     @Mock
     private PackageManager mPackageManager;
+    @Mock
+    private Resources mResources;
+
     private ActivityController<WallpaperSuggestionActivity> mController;
 
     @Before
@@ -72,6 +74,17 @@
     }
 
     @Test
+    public void wallpaperServiceEnabled_no_shouldReturnFalse() {
+        when(mContext.getResources()).thenReturn(mResources);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_enableWallpaperService)).thenReturn(false);
+
+        assertThat(WallpaperSuggestionActivity.isSuggestionComplete(mContext))
+                .isFalse();
+    }
+
+    @Test
+    @Config(shadows = WallpaperSuggestionActivityTest.ShadowWallpaperManagerWrapper.class)
     public void hasWallpaperSet_no_shouldReturnFalse() {
         ShadowWallpaperManagerWrapper.setWallpaperId(0);
 
@@ -80,6 +93,7 @@
     }
 
     @Test
+    @Config(shadows = WallpaperSuggestionActivityTest.ShadowWallpaperManagerWrapper.class)
     public void hasWallpaperSet_yes_shouldReturnTrue() {
         ShadowWallpaperManagerWrapper.setWallpaperId(100);
 
@@ -100,6 +114,15 @@
             sWallpaperId = 0;
         }
 
+        public void __constructor__(Context context) {
+
+        }
+
+        @Implementation
+        public boolean isWallpaperServiceEnabled() {
+            return true;
+        }
+
         @Implementation
         public int getWallpaperId(int which) {
             return sWallpaperId;