track all onTrimMemory levels excepted TRIM_MEMORY_UI_HIDDEN

I think we could make this cleaner by replacing lines 645-658 with this:
```
final boolean evictBitmaps;
switch (level) {
    case TRIM_MEMORY_COMPLETE:
        AnalyticsTracker.track(Stat.MEMORY_TRIMMED_COMPLETE);
        evictBitmaps = true;
        break;
    case TRIM_MEMORY_RUNNING_MODERATE:
    case TRIM_MEMORY_RUNNING_CRITICAL:
    case TRIM_MEMORY_RUNNING_LOW:
        Map<String, Integer> properties = new HashMap<String, Integer>();
        properties.put("level", level);
        AnalyticsTracker.track(Stat.MEMORY_TRIMMED, properties);
        evictBitmaps = true;
        break;
    default:
        evictBitmaps = false;
        break;
}

if (evictBitmaps && mBitmapCache != null) {
    mBitmapCache.evictAll();
}
```