[Settings] 1. Add configChange for WFC Activity to cover the changes of rotation and screen size

2. register split rule for MobileNetworkActivity

Bug: 204508876
Test: manual
Change-Id: Iff3dae41293e79b274d2928cb51efea46fb45dd4

src/com/android/settings/network/MobileNetworkTwoPaneUtils.java

@@ -0,0 +1,29 @@
+package com.android.settings.network;
+
+import android.annotation.Nullable;
+import android.content.Context;
+import android.content.Intent;
+import android.util.Log;
+
+import com.android.settings.activityembedding.ActivityEmbeddingRulesController;
+
+public class MobileNetworkTwoPaneUtils {
+
+    private static final String TAG = "MobileNetworkTwoPaneUtils";
+
+    /**
+     * TODO: b/206061070, the problem of multi-instance should be fixed in Android T to apply the
+     * Settings' architecture and 2 panes mode instead of registering the rule.
+     *
+     * The launchMode of MobileNetworkActivity is singleTask, set SplitPairRule to show in 2-pane.
+     */
+    public static void registerTwoPaneForMobileNetwork(Context context, Intent intent,
+            @Nullable String secondaryIntentAction) {
+        Log.d(TAG, "registerTwoPaneForMobileNetwork");
+        ActivityEmbeddingRulesController.registerTwoPanePairRuleForSettingsHome(
+                context,
+                intent.getComponent(),
+                secondaryIntentAction /* secondaryIntentAction */,
+                false /* clearTop */);
+    }
+}