Add subtext for Wi-Fi items on Wi-Fi slice

- Sync the Wi-Fi slice items subtexts with Wi-Fi page, and add
  "Not connected" when the returned subtext is empty
- Wi-Fi slice header subtext just simply reveals on/off state
- Add a placeholder to the loading row to sync its height with other
  rows
- Show contextual Wi-Fi slice when the connected network is captive
  portal, is invalidated, or has limited connectivity

Bug: 130751985
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.wifi
Change-Id: I0b2715295f00edc8dd7d6d75b7fdc18263675797

src/com/android/settings/wifi/slice/ContextualWifiSlice.java

@@ -17,7 +17,10 @@
 package com.android.settings.wifi.slice;
 
 import android.content.Context;
+import android.net.NetworkCapabilities;
 import android.net.Uri;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
 import android.net.wifi.WifiSsid;
 import android.text.TextUtils;
 import android.util.Log;
@@ -69,6 +72,22 @@ public class ContextualWifiSlice extends WifiSlice {
     }
 
     private boolean hasWorkingNetwork() {
-        return !TextUtils.equals(getActiveSSID(), WifiSsid.NONE) && !isCaptivePortal();
+        return !TextUtils.equals(getActiveSSID(), WifiSsid.NONE) && hasInternetAccess();
+    }
+
+    private String getActiveSSID() {
+        if (mWifiManager.getWifiState() != WifiManager.WIFI_STATE_ENABLED) {
+            return WifiSsid.NONE;
+        }
+        return WifiInfo.removeDoubleQuotes(mWifiManager.getConnectionInfo().getSSID());
+    }
+
+    private boolean hasInternetAccess() {
+        final NetworkCapabilities nc = mConnectivityManager.getNetworkCapabilities(
+                mWifiManager.getCurrentNetwork());
+        return nc != null
+                && !nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_CAPTIVE_PORTAL)
+                && !nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_PARTIAL_CONNECTIVITY)
+                && nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED);
     }
 }