hide launcher restore behind a flag.

enable with 'adb shell settings put secure launcher_restore_enabled 1'
before signing into wiped device

Bug: 12532845
Change-Id: I1471c39dac2e6e1412f7720b1ba8edf46273c593
diff --git a/src/com/android/launcher3/LauncherPreferencesBackupHelper.java b/src/com/android/launcher3/LauncherPreferencesBackupHelper.java
new file mode 100644
index 0000000..1ac6ff9
--- /dev/null
+++ b/src/com/android/launcher3/LauncherPreferencesBackupHelper.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3;
+
+import android.app.backup.BackupDataInputStream;
+import android.app.backup.SharedPreferencesBackupHelper;
+import android.content.Context;
+
+public class LauncherPreferencesBackupHelper extends SharedPreferencesBackupHelper {
+
+    private final boolean mRestoreEnabled;
+
+    public LauncherPreferencesBackupHelper(Context context,  String sharedPreferencesKey,
+            boolean restoreEnabled) {
+        super(context, sharedPreferencesKey);
+        mRestoreEnabled = restoreEnabled;
+    }
+
+    @Override
+    public void restoreEntity(BackupDataInputStream data) {
+        if (mRestoreEnabled) {
+            super.restoreEntity(data);
+        }
+    }
+}