Transition from DEV network stats to XT.

When XT stats are available, transition to prefer them over DEV,
since they aren't subject to hardware driver bugs.  Only switches at
the first atomic XT bucket, and adds a Settings.Secure flag to force
back to DEV if needed.  Includes tests to cover transition.

Fix tests where device overlay would change which network types
reflected data usage.  Test both history and summary APIs.  Fixed
collection timestamps to reflect full buckets.

Bug: 6504744
Change-Id: Idd7f3b2fdb064c36547c85c51c214fd938c59b7e

core/java/android/net/NetworkStats.java

@@ -111,6 +111,14 @@ public class NetworkStats implements Parcelable {
                     && operations == 0;
         }
 
+        public void add(Entry another) {
+            this.rxBytes += another.rxBytes;
+            this.rxPackets += another.rxPackets;
+            this.txBytes += another.txBytes;
+            this.txPackets += another.txPackets;
+            this.operations += another.operations;
+        }
+
         @Override
         public String toString() {
             final StringBuilder builder = new StringBuilder();

core/java/android/net/NetworkStatsHistory.java

@@ -342,11 +342,23 @@ public class NetworkStatsHistory implements Parcelable {
      * for combining together stats for external reporting.
      */
     public void recordEntireHistory(NetworkStatsHistory input) {
+        recordHistory(input, Long.MIN_VALUE, Long.MAX_VALUE);
+    }
+
+    /**
+     * Record given {@link NetworkStatsHistory} into this history, copying only
+     * buckets that atomically occur in the inclusive time range. Doesn't
+     * interpolate across partial buckets.
+     */
+    public void recordHistory(NetworkStatsHistory input, long start, long end) {
         final NetworkStats.Entry entry = new NetworkStats.Entry(
                 IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
         for (int i = 0; i < input.bucketCount; i++) {
-            final long start = input.bucketStart[i];
-            final long end = start + input.bucketDuration;
+            final long bucketStart = input.bucketStart[i];
+            final long bucketEnd = bucketStart + input.bucketDuration;
+
+            // skip when bucket is outside requested range
+            if (bucketStart < start || bucketEnd > end) continue;
 
             entry.rxBytes = getLong(input.rxBytes, i, 0L);
             entry.rxPackets = getLong(input.rxPackets, i, 0L);
@@ -354,7 +366,7 @@ public class NetworkStatsHistory implements Parcelable {
             entry.txPackets = getLong(input.txPackets, i, 0L);
             entry.operations = getLong(input.operations, i, 0L);
 
-            recordData(start, end, entry);
+            recordData(bucketStart, bucketEnd, entry);
         }
     }
 

core/java/android/net/NetworkTemplate.java

@@ -61,6 +61,13 @@ public class NetworkTemplate implements Parcelable {
                 com.android.internal.R.array.config_data_usage_network_types);
     }
 
+    private static boolean sForceAllNetworkTypes = false;
+
+    // @VisibleForTesting
+    public static void forceAllNetworkTypes() {
+        sForceAllNetworkTypes = true;
+    }
+
     /**
      * Template to match {@link ConnectivityManager#TYPE_MOBILE} networks with
      * the given IMSI.
@@ -225,7 +232,7 @@ public class NetworkTemplate implements Parcelable {
             // TODO: consider matching against WiMAX subscriber identity
             return true;
         } else {
-            return (contains(DATA_USAGE_NETWORK_TYPES, ident.mType)
+            return ((sForceAllNetworkTypes || contains(DATA_USAGE_NETWORK_TYPES, ident.mType))
                     && Objects.equal(mSubscriberId, ident.mSubscriberId));
         }
     }
@@ -291,7 +298,7 @@ public class NetworkTemplate implements Parcelable {
         if (ident.mType == TYPE_WIMAX) {
             return true;
         } else {
-            return contains(DATA_USAGE_NETWORK_TYPES, ident.mType);
+            return sForceAllNetworkTypes || contains(DATA_USAGE_NETWORK_TYPES, ident.mType);
         }
     }