Add a GN flag to allow sanitizer builds with full debugging symbols.

R=thakis@chromium.org
BUG=692620

Review-Url: https://codereview.chromium.org/2843773003
Cr-Original-Commit-Position: refs/heads/master@{#467178}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 2a7ed44b0ffb4f4e8f70dd5c0c82ad0046d84964
2 files changed