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
diff --git a/src/com/android/launcher3/DropTarget.java b/src/com/android/launcher3/DropTarget.java
index fd4c30c..70d8476 100644
--- a/src/com/android/launcher3/DropTarget.java
+++ b/src/com/android/launcher3/DropTarget.java
@@ -79,9 +79,7 @@
         public DraggableView originalView = null;
 
         /** Used for matching DROP event with its corresponding DRAG event on the server side. */
-        public final InstanceId logInstanceId =
-                new InstanceIdSequence(1 << 20 /*InstanceId.INSTANCE_ID_MAX*/)
-                    .newInstanceId();
+        public final InstanceId logInstanceId = new InstanceIdSequence().newInstanceId();
 
         public DragObject(Context context) {
             if (FeatureFlags.FOLDER_NAME_SUGGEST.get()) {
diff --git a/src/com/android/launcher3/logging/StatsLogManager.java b/src/com/android/launcher3/logging/StatsLogManager.java
index 2c5bf32..7e90769 100644
--- a/src/com/android/launcher3/logging/StatsLogManager.java
+++ b/src/com/android/launcher3/logging/StatsLogManager.java
@@ -29,8 +29,6 @@
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.util.ResourceBasedOverride;
 
-import java.util.List;
-
 /**
  * Handles the user event logging in R+.
  *
@@ -463,10 +461,4 @@
                 context.getApplicationContext(), R.string.stats_log_manager_class);
         return mgr;
     }
-
-    /**
-     * Logs impression of the current workspace with additional launcher events.
-     */
-    public void logSnapshot(List<EventEnum> additionalEvents) {
-    }
 }
diff --git a/src/com/android/launcher3/model/LoaderTask.java b/src/com/android/launcher3/model/LoaderTask.java
index d47fafd..b108788 100644
--- a/src/com/android/launcher3/model/LoaderTask.java
+++ b/src/com/android/launcher3/model/LoaderTask.java
@@ -289,6 +289,7 @@
             updateHandler.finish();
             logger.addSplit("finish icon update");
 
+            mModelDelegate.modelLoadComplete();
             transaction.commit();
         } catch (CancellationException e) {
             // Loader stopped, ignore
diff --git a/src/com/android/launcher3/model/ModelDelegate.java b/src/com/android/launcher3/model/ModelDelegate.java
index 3ed8809..92bea5b 100644
--- a/src/com/android/launcher3/model/ModelDelegate.java
+++ b/src/com/android/launcher3/model/ModelDelegate.java
@@ -78,6 +78,12 @@
     public void workspaceLoadComplete() { }
 
     /**
+     * Called at the end of model load task
+     */
+    @WorkerThread
+    public void modelLoadComplete() { }
+
+    /**
      * Called when the delegate is no loner needed
      */
     @WorkerThread