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}

When Chromium and V8 use the same version of inspector_protocol, any protocol change takes at least 4 patches and 3 waiting for rolls.
To simplify this process we need to have two diffrent versions of inspector_protocol in Chromium and V8. Current state of inspector_protocol was extracted into separate repository [1]. This CL puts last version of inspector_protocol into third_party/inspector_protocol and removes dependency on inspector_protocol in Webkit.

[1] https://chromium.googlesource.com/deps/inspector_protocol/

BUG=chromium:637032
R=dgozman@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2447323002
Cr-Commit-Position: refs/heads/master@{#40655}