Improve NetworkCapabilities command chaining.
Improve NetworkCapabilities command chaining.

setNetworkSpecifier() now returns this.
BUG: 26797290

Change-Id: Ia8bd0836d9ac715408eca102bf4a2d23f044fa72

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base