Merge "BatteryStats: Wifi energy data is sometimes wrong" into mnc-dev

            // correct delta from when we should start reading (aka when we are on battery).

            WifiActivityEnergyInfo info = mWifiManager.reportActivityInfo();

            if (info != null && info.isValid()) {

                if (info.mControllerEnergyUsed < 0 || info.mControllerIdleTimeMs < 0 ||

                        info.mControllerRxTimeMs < 0 || info.mControllerTxTimeMs < 0) {

                    Slog.wtf(TAG, "Reported WiFi energy data is invalid: " + info);

                    return null;

                }

                // We will modify the last info object to be the delta, and store the new

                // WifiActivityEnergyInfo object as our last one.

                final WifiActivityEnergyInfo result = mLastInfo;

                result.mTimestamp = info.getTimeStamp();

                result.mStackState = info.getStackState();

                // These times seem to be the most reliable.

                result.mControllerTxTimeMs =

                        info.mControllerTxTimeMs - mLastInfo.mControllerTxTimeMs;

                result.mControllerRxTimeMs =

                        info.mControllerRxTimeMs - mLastInfo.mControllerRxTimeMs;

                result.mControllerEnergyUsed =

                        info.mControllerEnergyUsed - mLastInfo.mControllerEnergyUsed;

                // WiFi calculates the idle time as a difference from the on time and the various

                // Rx + Tx times. There seems to be some missing time there because this sometimes

                // becomes negative. Just cap it at 0 and move on.

                // b/21613534

                result.mControllerIdleTimeMs =

                        Math.max(0, info.mControllerIdleTimeMs - mLastInfo.mControllerIdleTimeMs);

                result.mControllerEnergyUsed =

                        Math.max(0, info.mControllerEnergyUsed - mLastInfo.mControllerEnergyUsed);

                if (result.mControllerTxTimeMs < 0 ||

                        result.mControllerRxTimeMs < 0) {