Expose quota status for active network.

Create API to expose quota status derived from underlying network
policy.  This is designed to support applications making informed
decisions when performing network requests.

Fix bug with random stats generation, and write policy when changing
restrict background data flag.  Deprecate EXTRA_NETWORK_INFO, since
it varies based on UID.

Bug: 4517283, 5088603
Change-Id: Ic6893a8967f69937e466be226ba7bb86ef5a5d2d

services/java/com/android/server/ConnectivityService.java

@@ -40,6 +40,7 @@ import android.net.MobileDataStateTracker;
 import android.net.NetworkConfig;
 import android.net.NetworkInfo;
 import android.net.NetworkInfo.DetailedState;
+import android.net.NetworkQuotaInfo;
 import android.net.NetworkState;
 import android.net.NetworkStateTracker;
 import android.net.NetworkUtils;
@@ -737,6 +738,30 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         return result.toArray(new NetworkState[result.size()]);
     }
 
+    private NetworkState getNetworkStateUnchecked(int networkType) {
+        if (isNetworkTypeValid(networkType)) {
+            final NetworkStateTracker tracker = mNetTrackers[networkType];
+            if (tracker != null) {
+                return new NetworkState(tracker.getNetworkInfo(), tracker.getLinkProperties(),
+                        tracker.getLinkCapabilities());
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public NetworkQuotaInfo getActiveNetworkQuotaInfo() {
+        enforceAccessPermission();
+        final NetworkState state = getNetworkStateUnchecked(mActiveDefaultNetwork);
+        if (state != null) {
+            try {
+                return mPolicyManager.getNetworkQuotaInfo(state);
+            } catch (RemoteException e) {
+            }
+        }
+        return null;
+    }
+
     public boolean setRadios(boolean turnOn) {
         boolean result = true;
         enforceChangePermission();