Cleaning up LauncherModel

- performing all DB operations immediately if called from worker thread (a previous change that did this in updateItemInDatabase fixed an outstanding bug)
- centralizing logic to do database updates
- removing old logging code

Change-Id: Idc7bfef3921828ff7c5492b8e996c0a07e1ec508

src/com/android/launcher2/InstallWidgetReceiver.java

@@ -187,7 +187,7 @@ public class InstallWidgetReceiver {
             final AppWidgetProviderInfo widgetInfo = mActivities.get(which).widgetInfo;
 
             final PendingAddWidgetInfo createInfo = new PendingAddWidgetInfo(widgetInfo, mMimeType,
-                    mClipData, "4");
+                    mClipData);
             mLauncher.addAppWidgetFromDrop(createInfo, LauncherSettings.Favorites.CONTAINER_DESKTOP,
                     mTargetLayoutScreen, null, mTargetLayoutPos);
         }