Add a screen to show OEM backup settings.

Moves the backup settings logic to BackupSettingsHelper and
BackupSettingsActivity:
- If the manufacturer provides the intent and the label for their backup
settings in the config.xml, a new intermediate fragment is shown for
Backup settings to let the user pick either standard backup settings or
OEM provided backup settings.
- If config.xml doesn't contain the intent, BackupSettingsActivity is
used as a trampoline activity to launch backup settings provided by the
backup transport of the default backup settings activity, i.e.
PrivacySettingsActivity.

Bug: 34700410
Bug: 33655074
Bug: 33654991
Test: make RunSettingsRoboTests
Change-Id: I78e340fbf926b2a9dc2c4e3942f9337c3c7a933c

src/com/android/settings/backup/BackupSettingsActivity.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2017 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.settings.backup;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.util.Log;
+
+
+/**
+ * The activity used to launch the configured Backup activity or the preference screen
+ * if the manufacturer provided their backup settings.
+ */
+public class BackupSettingsActivity extends Activity {
+    private static final String TAG = "BackupSettingsActivity";
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        BackupSettingsHelper backupHelper = new BackupSettingsHelper(this);
+
+        if (!backupHelper.isBackupProvidedByManufacturer()) {
+            // If manufacturer specific backup settings are not provided then launch
+            // the backup settings provided by backup transport or the default one directly.
+            if (Log.isLoggable(TAG, Log.DEBUG)) {
+                Log.d(TAG,
+                        "No manufacturer settings found, launching the backup settings directly");
+            }
+            // use startActivityForResult to let the activity check the caller signature
+            startActivityForResult(backupHelper.getIntentForBackupSettings(), 1);
+            finish();
+        } else {
+            if (Log.isLoggable(TAG, Log.DEBUG)) {
+                Log.d(TAG, "Manufacturer provided backup settings, showing the preference screen");
+            }
+            getFragmentManager().beginTransaction()
+                    .replace(android.R.id.content, new BackupSettingsFragment())
+                    .commit();
+        }
+    }
+}