Extending the grid migration logic to handle density changes

For hotseat migratino, we simply drop the items with least weight
If the workspace row/column decreases by 2 or more, we clear the whole workspace

Bug: 25958224
Change-Id: I7131b955023d185ed10955f593184b9238546dc8
diff --git a/src/com/android/launcher3/LauncherBackupAgentHelper.java b/src/com/android/launcher3/LauncherBackupAgentHelper.java
index 0773bf2..bf9c668 100644
--- a/src/com/android/launcher3/LauncherBackupAgentHelper.java
+++ b/src/com/android/launcher3/LauncherBackupAgentHelper.java
@@ -24,7 +24,7 @@
 import android.os.ParcelFileDescriptor;
 import android.util.Log;
 
-import com.android.launcher3.model.MigrateFromRestoreTask;
+import com.android.launcher3.model.GridSizeMigrationTask;
 
 import java.io.IOException;
 
@@ -101,8 +101,9 @@
                         LauncherSettings.Settings.METHOD_UPDATE_FOLDER_ITEMS_RANK);
             }
 
-            if (MigrateFromRestoreTask.ENABLED && mHelper.shouldAttemptWorkspaceMigration()) {
-                MigrateFromRestoreTask.markForMigration(getApplicationContext(),
+            // TODO: Update this logic to handle grid difference of 2. as well as hotseat difference
+            if (GridSizeMigrationTask.ENABLED && mHelper.shouldAttemptWorkspaceMigration()) {
+                GridSizeMigrationTask.markForMigration(getApplicationContext(),
                         (int) mHelper.migrationCompatibleProfileData.desktopCols,
                         (int) mHelper.migrationCompatibleProfileData.desktopRows,
                         mHelper.widgetSizes);