Avoid recording negative data by doing integer-based
math as much as possible, but switch to double-based
math if we detect that we'd end up causing an overflow.
Test :
- Builds, Boots
- High data throughput scenarios
- NetworkStatsHistoryTest, NetworkStatsCollectionTest,
NetworkStatsTest
Bug: 119527458
Change-Id: I55d4aa649bea3ae201ad513074ff2b71cb918dad
fc5b6cb326