Do not overwrite user set or live wallpapers

WallpaperUpdateReceiver unconditionally updates the wallpaper
to the default_wallpaper when DEVICE_CUSTOMIZATION_READY is
received.

This overwrites live wallpapers and user set wallpapers.
Just clear the wallpaper when there is no live wallpaper to
avoid this from happening.

Test: set a wallpaper and run
adb shell am broadcast \
  -a android.intent.action.DEVICE_CUSTOMIZATION_READY \
  -f 0x01000000

Bug: 159673283
Change-Id: I385c28be84b9146e8620910258495f5d71b9c04e

services/core/java/com/android/server/WallpaperUpdateReceiver.java

@@ -24,7 +24,6 @@ import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
-import android.graphics.Bitmap;
 import android.os.AsyncTask;
 import android.os.ParcelFileDescriptor;
 import android.util.Slog;
@@ -59,10 +58,10 @@ public class WallpaperUpdateReceiver extends BroadcastReceiver {
                 return;
             }
             if (DEBUG) Slog.d(TAG, "Set customized default_wallpaper.");
-            Bitmap blank = Bitmap.createBitmap(1, 1, Bitmap.Config.ALPHA_8);
-            // set a blank wallpaper to force a redraw of default_wallpaper
-            wallpaperManager.setBitmap(blank);
-            wallpaperManager.setResource(com.android.internal.R.drawable.default_wallpaper);
+            // Check if it is not a live wallpaper set
+            if (wallpaperManager.getWallpaperInfo() == null) {
+                wallpaperManager.clearWallpaper();
+            }
         } catch (Exception e) {
             Slog.w(TAG, "Failed to customize system wallpaper." + e);
         }