Revert onSurfaceRedrawNeeded behavior

The wallpaper bitmap will be unloaded after a few seconds to
free memory, this means that onSurfaceRedrawNeeded would need
to synchronously load an image, which may delay app launches.

Test: manually rotate screen
Change-Id: Ib4987265e5a1dd113b7cd2c8ea7c9d8f8ce5a8f3
Fixes: 110732172

packages/SystemUI/src/com/android/systemui/ImageWallpaper.java

@@ -256,12 +256,6 @@ public class ImageWallpaper extends WallpaperService {
                 Log.d(TAG, "onSurfaceRedrawNeeded");
             }
             super.onSurfaceRedrawNeeded(holder);
-            // At the end of this method we should have drawn into the surface.
-            // This means that the bitmap should be loaded synchronously if
-            // it was already unloaded.
-            if (mBackground == null) {
-                updateBitmap(mWallpaperManager.getBitmap(true /* hardware */));
-            }
             mSurfaceRedrawNeeded = true;
             drawFrame();
         }