Convert dataDuringCall to autoDataSWitch

The feature is enabled via
TelephonyManager.MOBILE_DATA_POLICY_AUTO_DATA_SWITCH. The feature only
applies to non-DDS. If enabled, we automatically switch to the non-DDS for data traffic when it has better availability than the DDS.

The UI change are(as required by b/247880971):
1. data during call is replaced by auto data switch, and moved under
   mobile data toggle.
2. Network & internet and Internet page now show the currently active
   subscription, instead of the defalut subscription. If the currently
   active sub is not the default, it's reflected in summary as
   "temporarily".

Test: manual
Bug: 244064524
Change-Id: Ica1eba99cee0d4af528d58f1c7bd1439400bfa66

src/com/android/settings/network/telephony/AutoDataSwitchPreferenceController.java

@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2019 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.network.telephony;
+
+import static androidx.lifecycle.Lifecycle.Event.ON_PAUSE;
+import static androidx.lifecycle.Lifecycle.Event.ON_RESUME;
+
+import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+import androidx.preference.SwitchPreference;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.settings.datausage.DataUsageUtils;
+import com.android.settings.network.MobileDataContentObserver;
+import com.android.settings.network.SubscriptionsChangeListener;
+
+/**
+ * Controls whether switch mobile data to the non-default SIM if the non-default SIM has better
+ * availability.
+ *
+ * This is used for temporarily allowing data on the non-default data SIM when on-default SIM
+ * has better availability on DSDS devices, where better availability means strong
+ * signal/connectivity.
+ * If this feature is enabled, data will be temporarily enabled on the non-default data SIM,
+ * including during any voice calls.
+ */
+public class AutoDataSwitchPreferenceController extends TelephonyTogglePreferenceController
+        implements LifecycleObserver,
+        SubscriptionsChangeListener.SubscriptionsChangeListenerClient {
+
+    private SwitchPreference mPreference;
+    private SubscriptionsChangeListener mChangeListener;
+    private TelephonyManager mManager;
+    private MobileDataContentObserver mMobileDataContentObserver;
+    private PreferenceScreen mScreen;
+
+    public AutoDataSwitchPreferenceController(Context context,
+            String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    void init(int subId) {
+        this.mSubId = subId;
+        mManager = mContext.getSystemService(TelephonyManager.class).createForSubscriptionId(subId);
+    }
+
+    @OnLifecycleEvent(ON_RESUME)
+    public void onResume() {
+        if (mChangeListener == null) {
+            mChangeListener = new SubscriptionsChangeListener(mContext, this);
+        }
+        mChangeListener.start();
+        if (mMobileDataContentObserver == null) {
+            mMobileDataContentObserver = new MobileDataContentObserver(
+                    new Handler(Looper.getMainLooper()));
+            mMobileDataContentObserver.setOnMobileDataChangedListener(() -> refreshPreference());
+        }
+        mMobileDataContentObserver.register(mContext, mSubId);
+    }
+
+    @OnLifecycleEvent(ON_PAUSE)
+    public void onPause() {
+        if (mChangeListener != null) {
+            mChangeListener.stop();
+        }
+        if (mMobileDataContentObserver != null) {
+            mMobileDataContentObserver.unRegister(mContext);
+        }
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+        mScreen = screen;
+    }
+
+    @Override
+    public boolean isChecked() {
+        return mManager.isMobileDataPolicyEnabled(
+                TelephonyManager.MOBILE_DATA_POLICY_AUTO_DATA_SWITCH);
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        mManager.setMobileDataPolicyEnabled(
+                TelephonyManager.MOBILE_DATA_POLICY_AUTO_DATA_SWITCH,
+                isChecked);
+        return true;
+    }
+
+    @VisibleForTesting
+    protected boolean hasMobileData() {
+        return DataUsageUtils.hasMobileData(mContext);
+    }
+
+    @Override
+    public int getAvailabilityStatus(int subId) {
+        if (!SubscriptionManager.isValidSubscriptionId(subId)
+                || SubscriptionManager.getDefaultDataSubscriptionId() == subId
+                || (!hasMobileData())) {
+            return CONDITIONALLY_UNAVAILABLE;
+        }
+        return AVAILABLE;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        super.updateState(preference);
+        if (preference == null) {
+            return;
+        }
+        preference.setVisible(isAvailable());
+    }
+
+    @Override
+    public void onAirplaneModeChanged(boolean airplaneModeEnabled) {}
+
+    @Override
+    public void onSubscriptionsChanged() {
+        updateState(mPreference);
+    }
+
+    /**
+     * Trigger displaying preference when Mobilde data content changed.
+     */
+    @VisibleForTesting
+    public void refreshPreference() {
+        if (mScreen != null) {
+            super.displayPreference(mScreen);
+        }
+    }
+}