[DevTools] Schema domain implementation.

One can query domain names and versions.
v8_inspector provides it's own implementation, while browser has a hardcoded list for now.

BUG=635947,635953

Review-Url: https://codereview.chromium.org/2253383002
Cr-Original-Commit-Position: refs/heads/master@{#413561}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 1c000dbd6fbdf95e745f907540aa43e6be20ecec