Add NetworkRequest.Builder creating from an existing instance

Provide a formal way to construct a new NetworkRequest from an
existing instance. The network capabilities inside the
NetworkRequest is hidden. There is no way to pass a
NetworkRequest and update its capabilities. Add
NetworkRequest.Builder creating from an existing instance to
allow to clone the network capabilities.

Bug: 172183305
Test: make update-api
Change-Id: I068462b2a1410daf67b0c95f2b643d396f079531
Merged-In: I068462b2a1410daf67b0c95f2b643d396f079531
2 files changed
tree: 18dbe0aa65d26b6eb80b50b0bc95ed94750cdc76
  1. framework/
  2. service/
  3. OWNERS
  4. TEST_MAPPING