GitLab

Enable feedback-directed optimisation for the main library (required to
make the FDO symbols present at link time), skia, and sqlite. Update the
android_exports whitelist to allow the gcov symbols to remain public as
otherwise profiling will fail.

BUG=
TBR=michaeln@chromium.org

Review URL: https://codereview.chromium.org/591153002

Cr-Commit-Position: refs/heads/master@{#296997}