Cleanup the private members in IpClientNetlinkMonitor.

Move private members: mShim, mExpirePref64Alarm and mNat64PrefixExpiry
out of IpClientNetlinkMonitor class, and initialize them at constructor.

Bug: 318764217
Test: atest NetworkStackTest
Test: atest NetworkStackIntegrationTests
Change-Id: I5df9eed49a7f5d6ed4358face065a5b1b11cd0be
1 file changed