Some improvements for wallpaper configuration.

This introduces a new activity that you can derive from to implement
a wall paper configuration activity.  This is supposed to select
a theme based on whether it is being run to configure a real wallpaper
or a preview, but this is going to be more difficult to do than I
thought. :(

Also fix a problem in the white theme where the list view's background
was being set to white, so it wouldn't work on a transparent bg.

Change-Id: I26d5a8695a3c878a1664eb09900eded57eaff990

services/java/com/android/server/WindowManagerService.java

@@ -1244,12 +1244,6 @@ public class WindowManagerService extends IWindowManager.Stub
                             "Skipping hidden or animating token: " + w);
                     continue;
                 }
-                // If this window's app token is ot fullscreen, also irrelevant.
-                if (!w.mAppToken.appFullscreen) {
-                    if (DEBUG_WALLPAPER) Log.v(TAG,
-                            "Skipping non-fullscreen token: " + w);
-                    continue;
-                }
             }
             if (DEBUG_WALLPAPER) Log.v(TAG, "Win " + w + ": readyfordisplay="
                     + w.isReadyForDisplay() + " drawpending=" + w.mDrawPending