idl: Update IDL parser to accept includes

"includes" statement is newly defined in Web IDL grammar.
This CL updates IDL parser to accept it as a correct tree.


Bug: 781257
Change-Id: I934764ee6698d34a6852138235d8f71641e2d3fe
Reviewed-on: https://chromium-review.googlesource.com/955702
Reviewed-by: Kentaro Hara <[email protected]>
Reviewed-by: Kenichi Ishibashi <[email protected]>
Commit-Queue: Hitoshi Yoshida <[email protected]>
Cr-Commit-Position: refs/heads/master@{#542378}
4 files changed