Fix issue #3420898: More wallpaper issues

- The ImageWallpaper wasn't watching for the desired dimensions to
  change, at which point it needs to resize its surface.
- The system process has been running with the small dalvik heap
  limit, which is too tight with these huge wallpapers; this would
  cause switching wallpapers to eventually stop working as it
  couldn't get the memory it needed to load the new one.
- The compatibility mode background surface had a bunch of issues,
  such as moving its windows to the right by the window size to
  make them disappear.  This of course doesn't play well with the
  now super-sized wallpaper surface.  This code is re-worked to
  not require such shenanigans.

Change-Id: I64fde4059645d8507f1c4761ba6c17b89877a5c0

services/java/com/android/server/SystemServer.java

@@ -629,6 +629,9 @@ public class SystemServer {
             }, SNAPSHOT_INTERVAL, SNAPSHOT_INTERVAL);
         }
 
+        // Mmmmmm... more memory!
+        dalvik.system.VMRuntime.getRuntime().clearGrowthLimit();
+
         // The system server has to run all of the time, so it needs to be
         // as efficient as possible with its memory usage.
         VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);