GitLab

When chromedriver is built with a dynamically linked ffmpeg on macOS
we need to set the rpath so that ffmpeg.dylib is loaded correctly.

Change-Id: I204810ac8610375aa8b0a2e7fae78464c1a3371e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2033343Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Jeremy Apthorp <jeremya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737510}