[Settings] Apply proxy design to data usage

Enable proxy to subscription manager in data usage UI.

Bug: 141833767
Test: manual
make RunSettingsRoboTests -j ROBOTEST_FILTER=BillingCyclePreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=CellDataPreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageListTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageSummaryTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageUtilsTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=MobileDataEnabledListenerTest

Change-Id: Id119738dc16ece8767c088b9a0794997e4b0334f

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

@@ -82,7 +82,6 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
             }
         };
 
-        mKeepCacheWhenOnStart = true;
         mSubsciptionsMonitor.start();
     }
 
@@ -90,7 +89,6 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
     private Context mContext;
     private ActiveSubsciptionsListener mSubsciptionsMonitor;
     private GlobalSettingsChangeListener mAirplaneModeMonitor;
-    private boolean mKeepCacheWhenOnStart;
 
     private List<OnActiveSubscriptionChangedListener> mActiveSubscriptionsListeners;
 
@@ -100,6 +98,12 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
         }
     }
 
+    @Override
+    public void onSubscriptionsChanged() {
+        clearCache();
+        notifyAllListeners();
+    }
+
     /**
      * Lifecycle for data within proxy
      *
@@ -118,15 +122,11 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
 
     @OnLifecycleEvent(ON_START)
     void onStart() {
-        if (!mKeepCacheWhenOnStart) {
-            mSubsciptionsMonitor.clearCache();
-        }
         mSubsciptionsMonitor.start();
     }
 
     @OnLifecycleEvent(ON_STOP)
     void onStop() {
-        mKeepCacheWhenOnStart = false;
         mSubsciptionsMonitor.stop();
     }
 
@@ -151,6 +151,15 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
         return mSubsciptionsMonitor.getSubscriptionManager();
     }
 
+    /**
+     * Get current max. number active subscription info(s) been setup within device
+     *
+     * @return max. number of active subscription info(s)
+     */
+    public int getActiveSubscriptionInfoCountMax() {
+        return mSubsciptionsMonitor.getActiveSubscriptionInfoCountMax();
+    }
+
     /**
      * Get a list of active subscription info
      *
@@ -183,6 +192,9 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
      * @param listener listener to active subscriptions change
      */
     public void addActiveSubscriptionsListener(OnActiveSubscriptionChangedListener listener) {
+        if (mActiveSubscriptionsListeners.contains(listener)) {
+            return;
+        }
         mActiveSubscriptionsListeners.add(listener);
     }