private void startWifiDisplayScanLocked(CallbackRecord record) {
   if (!record.mWifiDisplayScanRequested) {
     record.mWifiDisplayScanRequested = true;
     if (mWifiDisplayScanRequestCount++ == 0) {
       if (mWifiDisplayAdapter != null) {
         mWifiDisplayAdapter.requestStartScanLocked();
       }
     }
   }
 }
 private void stopWifiDisplayScanLocked(CallbackRecord record) {
   if (record.mWifiDisplayScanRequested) {
     record.mWifiDisplayScanRequested = false;
     if (--mWifiDisplayScanRequestCount == 0) {
       if (mWifiDisplayAdapter != null) {
         mWifiDisplayAdapter.requestStopScanLocked();
       }
     } else if (mWifiDisplayScanRequestCount < 0) {
       Log.wtf(
           TAG, "mWifiDisplayScanRequestCount became negative: " + mWifiDisplayScanRequestCount);
       mWifiDisplayScanRequestCount = 0;
     }
   }
 }