Determine whether the cell location is updated when the screen is off

I found that some phones do not update the current сell location when display is off. The `mTelephonyManager.getCellLocation()` returns the same value until the screen is turned on, though, in fact, the current cell changes. 
If you go with such phone at a high speed for a long time, the phone incorrectly reports signal from the cell tower over the long distance.
My solution is to watch for changes when the screen is off and do not take into account cell location data until it is at-least one change.
Related bug: https://code.google.com/p/android/issues/detail?id=10931