WallpaperPreferences update for live wallpapers

- Add wallpaper service name into WallpaperPreferences.
- Add missing keys for clearLockWallpaperMetadata.

Test: Manual
Bug: 156345208
Change-Id: Id82e13150f8664c05edee30465233cc24dfc9e31
diff --git a/src/com/android/wallpaper/module/WallpaperPreferences.java b/src/com/android/wallpaper/module/WallpaperPreferences.java
index 8857ed4..27cd89e 100755
--- a/src/com/android/wallpaper/module/WallpaperPreferences.java
+++ b/src/com/android/wallpaper/module/WallpaperPreferences.java
@@ -143,6 +143,16 @@
     void setHomeWallpaperPackageName(String packageName);
 
     /**
+     * Gets the home wallpaper's service name, which is present for live wallpapers.
+     */
+    String getHomeWallpaperServiceName();
+
+    /**
+     * Sets the home wallpaper's service name, which is present for live wallpapers.
+     */
+    void setHomeWallpaperServiceName(String serviceName);
+
+    /**
      * Gets the home wallpaper's ID, which is provided by WallpaperManager for static wallpapers.
      */
     @TargetApi(Build.VERSION_CODES.N)