Implementation of DevToolsBridgeServer.
Basic functionality for android's server and tests. Isolated from GCD code.
New button in the debugging activity causes equivalent result with previous one (tunnels a real DevTools socket to a fake one) but uses android service for that (2 ways of tasting may help in bug triaging). It lets test service life cycle and UI (foreground notification).
BUG=
383418
TEST=DevToolsBridgeServerTest, new button in debugging activity for manual testing
Committed:
https://crrev.com/853b6724ef2bf19c6181e40d364213bf3b3a7613
Cr-Commit-Position: refs/heads/master@{#300091}