The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bcb04df7b744ea57e45e0a45188193bdb68b9ce4

commit bcb04df7b744ea57e45e0a45188193bdb68b9ce4
Author: Robert Flack <flackr@chromium.org>
Date: Thu Mar 01 21:00:17 2018

Symlink default rr trace directory in dummy home directory.

rr defaults to writing the trace to $HOME/.local/share/rr but run-webkit-tests
creates a dummy home directory that is deleted after tests run. In order to
make this "just work" we can symlink .local/share/rr to the real directory if
it exists.

Bug:  817861 
Change-Id: I845c023c3be98835bddb757dad9a18231c7e69ce
Reviewed-on: https://chromium-review.googlesource.com/943826
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540281}
[modify] https://crrev.com/bcb04df7b744ea57e45e0a45188193bdb68b9ce4/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/linux.py