Use scaled display size in wallpaper constraint.

Bug:11596190
Change-Id: Icc81beeea2e71144c2e5330b047e4781a23d7449
diff --git a/services/java/com/android/server/WallpaperManagerService.java b/services/java/com/android/server/WallpaperManagerService.java
index e25470c..e6b6b93 100644
--- a/services/java/com/android/server/WallpaperManagerService.java
+++ b/services/java/com/android/server/WallpaperManagerService.java
@@ -640,11 +640,9 @@
 
     private Point getDefaultDisplaySize() {
         Point p = new Point();
-        try {
-            mIWindowManager.getInitialDisplaySize(Display.DEFAULT_DISPLAY, p);
-        } catch (RemoteException e) {
-            // not remote
-        }
+        WindowManager wm = (WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE);
+        Display d = wm.getDefaultDisplay();
+        d.getRealSize(p);
         return p;
     }