Includes:
- Better windows support in json generator.
- Add PDL2JSON, don't paste descriptions as comments into generated code.
- [inspector_protocol] generated only used types

R=pfeldman@chromium.org

Bug: none
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I3c634359b3ac4b00293ac7c5ee224dab53aae7ca
Reviewed-on: https://chromium-review.googlesource.com/810204
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49949}