Reason for revert:
Causes regressions.
Original issue's description:
> [build] Use -O2 on linux by default
>
> This switches O2 -> O3 to match chromium's configuration.
>
> This makes the difference between gn and gyp a bit smaller
> before switching.
>
> BUG=chromium:474921
> LOG=n
>
> Committed: https://crrev.com/a37ab71e343b8cc24df05868b941a49e0c271376
> Cr-Commit-Position: refs/heads/master@{#36124}
TBR=jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921
Review-Url: https://codereview.chromium.org/1958253004
Cr-Commit-Position: refs/heads/master@{#36135}
This switches O2 -> O3 to match chromium's configuration.
This makes the difference between gn and gyp a bit smaller
before switching.
BUG=chromium:474921
LOG=n
Review-Url: https://codereview.chromium.org/1963693004
Cr-Commit-Position: refs/heads/master@{#36124}
This prepares for pulling chromium's build as dependency for
gn. After this, the files in build and gypfiles need to stay
in sync until chromium is updated.
BUG=chromium:474921
LOG=n
Review-Url: https://codereview.chromium.org/1848553003
Cr-Commit-Position: refs/heads/master@{#35898}
