GitLab

document: Update IDLExtendedAttributes.md

Update IDLExtendedAttributes.md to be more consistent with
current implementations.

Specifically, this CL does
- Make targets of applicable-to-types ext. attr. clear.
- Update C++ implmentations to meet current coding style
- Remove trailing commas in WebIDL. It's now disallowed.
- Update few descriptions.


Bug: None
Change-Id: I39fb50699cd8f6bf3ed7fb74e8304c8ed476e0d3
Reviewed-on: https://chromium-review.googlesource.com/c/1343873Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609639}