ConfigWifiDisableInEcbm: add null check and change default value

1. CarrierConfigManager#getConfig() is @Nullable, so perform a
    null check to avoid NPE.
2. Change the default value from true to false to be consistent
    with the declaration of KEY_CONFIG_WIFI_DISABLE_IN_ECBM in
    CarrierConfigManager.

The initial commits (under the same topic no less) were
contradictory regarding the default values.
I5af370c143630bdd4b075f4730fd1de1bbe1fe7d states in the commit
message and code that the default should be false, but
If1724f825f1c8b47ec2f29ecd8abda45ef9bc393 has the default
value set to true.

Bug: 156962944
Test: compiles
Change-Id: I87c4d9380d6ab1f8b74c58ec8a91de4003eec426

1 files changed, 8 insertions, 5 deletions

diff --git a/service/java/com/android/server/wifi/FrameworkFacade.java b/service/java/com/android/server/wifi/FrameworkFacade.java
index a0b510f0f..875154e5b 100644
--- a/service/java/com/android/server/wifi/FrameworkFacade.java
+++ b/service/java/com/android/server/wifi/FrameworkFacade.java
@@ -32,6 +32,7 @@ import android.net.TrafficStats;
 import android.net.Uri;
 import android.net.ip.IpClientCallbacks;
 import android.net.ip.IpClientUtil;
+import android.os.PersistableBundle;
 import android.provider.Settings;
 import android.telephony.CarrierConfigManager;
 import android.util.Log;
@@ -173,12 +174,14 @@ public class FrameworkFacade {
 
     public boolean getConfigWiFiDisableInECBM(Context context) {
         CarrierConfigManager configManager = getCarrierConfigManager(context);
-        if (configManager != null) {
-            return configManager.getConfig().getBoolean(
-                    CarrierConfigManager.KEY_CONFIG_WIFI_DISABLE_IN_ECBM);
+        if (configManager == null) {
+            return false;
         }
-        /* Default to TRUE */
-        return true;
+        PersistableBundle bundle = configManager.getConfig();
+        if (bundle == null) {
+            return false;
+        }
+        return bundle.getBoolean(CarrierConfigManager.KEY_CONFIG_WIFI_DISABLE_IN_ECBM);
     }
 
     public long getTxPackets(String iface) {