Integrating snapshot logging in Launcher

> Workspace snapshot is logged when the workspace loads (at most once a day)
> Removing unnecessary thread jumping when logging folders
> Preference snapshot is logged on process start and whenever something changes

Change-Id: I93767de89b11522d843c0e8300d1f108c78f6d90

src/com/android/launcher3/model/LoaderTask.java

@@ -289,6 +289,7 @@ public class LoaderTask implements Runnable {
             updateHandler.finish();
             logger.addSplit("finish icon update");
 
+            mModelDelegate.modelLoadComplete();
             transaction.commit();
         } catch (CancellationException e) {
             // Loader stopped, ignore