Cache widget previews in a DB

- Smoother All Apps scroll performance

Change-Id: Id2d31a45e71c63d05a46f580667ad94403730616
diff --git a/src/com/android/launcher2/LauncherModel.java b/src/com/android/launcher2/LauncherModel.java
index ccf8328..9a5bd47 100644
--- a/src/com/android/launcher2/LauncherModel.java
+++ b/src/com/android/launcher2/LauncherModel.java
@@ -1988,6 +1988,7 @@
                     for (int i=0; i<N; i++) {
                         if (DEBUG_LOADERS) Log.d(TAG, "mAllAppsList.updatePackage " + packages[i]);
                         mBgAllAppsList.updatePackage(context, packages[i]);
+                        WidgetPreviewLoader.removeFromDb(context, packages[i]);
                     }
                     break;
                 case OP_REMOVE:
@@ -1995,6 +1996,7 @@
                     for (int i=0; i<N; i++) {
                         if (DEBUG_LOADERS) Log.d(TAG, "mAllAppsList.removePackage " + packages[i]);
                         mBgAllAppsList.removePackage(packages[i]);
+                        WidgetPreviewLoader.removeFromDb(context, packages[i]);
                     }
                     break;
             }