commit e88f5efeb94bd19b0f6453c622b6e333852b4414
author govenliu <govenliu@google.com> Mon Feb 03 11:25:41 2020 +0800
committer govenliu <govenliu@google.com> Tue Feb 04 10:40:55 2020 +0800
tree 6c93a9157c2a765c77d208fecd40e2faa2991a9b
parent d737601a66fb7adc89d8451a6daf16b9b394cf1c

[Wi-Fi] Apply cache in WifiTracker to update the signal icon immediatelly.

issue: Signal icon on the add wifi network feature need to wait for the scan result.
Solution: Apply the cache in the WifiTracker to update signal icon for
shortening the waiting time of new scan result.

Bug: 146842198
Test: Add following unit test cases to test signal level has been updated correctly:
      1. withOneSuggestion_whenScanResultChangedButWifiOff_uiListShouldHaveZeroLevel.

Change-Id: Id72e2b43e020f2cafa2af4af5ffb1c28529002bd