Guard some accessibility code that requires a newer atk lib

On some development platforms (like Ubuntu 16.04 LTS), newer
atk libraries are not available so code need to be optional.

For production builds a sysroot with all the required libraries
must be used.

This adds checks for Atk 2.30 to some places, and changes the
ifdef style to be the same in all checks.

Change-Id: Iec48dd31774a5ba148a71ecb545befe4339d860c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614205
Auto-Submit: Daniel Bratell <bratell@opera.com>
Commit-Queue: Martin Robinson <mrobinson@igalia.com>
Reviewed-by: Martin Robinson <mrobinson@igalia.com>
Cr-Commit-Position: refs/heads/master@{#660750}
2 files changed