This roll includes:
  - [inspector_protocol] Introduce protocol::Serializable [1]

[1] https://codereview.chromium.org/2526603002

BUG=chromium:350797
R=dgozman@chromium.org

Review-Url: https://codereview.chromium.org/2523583005
Cr-Commit-Position: refs/heads/master@{#41197}