Revert of Enable ThinLTO and LLD for POSIX LTO by default on Linux.

Revert of Enable ThinLTO and LLD for POSIX LTO by default on Linux. (patchset #4 id:60001 of https://codereview.chromium.org/2831213006/ )

Reason for revert:
Code size increase: https://chromeperf.appspot.com/report?sid=7826328365affe1842778994c934cbe08c7f9b78ef5d8895ec85d3094bb8972d&start_rev=466555&end_rev=466782

Postmortem is coming. TL;DR: worse dead code elimination in ThinLTO

Original issue's description:
> Enable ThinLTO and LLD for POSIX LTO by default on Linux.
> 
> Eventually, we will enable LLD on Linux even for regular
> builds, but it's natural to make incremental steps here.
> 
> ThinLTO brings multi-threaded linking for LinkTimeOptimization
> builds, which allows to speed up codegen considerably (up to 4x).
> ThinLTO also manages a cache inside out/<gn-config>/thinlto-cache
> directory, that improves incremental linking as well.
> 
> There's a cache pruning policy that will prevent the cache from
> growing indefinitely. The policy is not yet finalized, and
> complaints / suggestions are welcome.
> 
> BUG=660216, 607968
> 
> Review-Url: https://codereview.chromium.org/2831213006
> Cr-Commit-Position: refs/heads/master@{#466732}
> Committed: https://chromium.googlesource.com/chromium/src/+/7997bbe88aef7eeca37111dcb8426f0430347fb5

TBR=dpranke@chromium.org,thakis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660216, 607968
Review-Url: https://codereview.chromium.org/2842683002
Cr-Commit-Position: refs/heads/master@{#466842}
Committed: https://chromium.googlesource.com/chromium/src/+/6aee4d67dcc67850c8ec7b9fc181cb7d91b55734

[krasin1, 2017-04-25 00:41:17]

The CQ bit was checked by krasin@chromium.org

[krasin1, 2017-04-25 00:41:18]

Created Revert of Enable ThinLTO and LLD for POSIX LTO by default on Linux.

[commit-bot: I haz the power, 2017-04-25 00:41:42]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-25 00:42:04]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493080877752720, "parent_rev":
"98593cf1c4918b063b60627f439d8f97cd6489ab", "commit_rev":
"6aee4d67dcc67850c8ec7b9fc181cb7d91b55734"}

[commit-bot: I haz the power, 2017-04-25 00:42:37]

Description was changed from

==========
Revert of Enable ThinLTO and LLD for POSIX LTO by default on Linux. (patchset #4
id:60001 of https://codereview.chromium.org/2831213006/ )

Reason for revert:
Code size increase:
https://chromeperf.appspot.com/report?sid=7826328365affe1842778994c934cbe08c7...

Postmortem is coming. TL;DR: worse dead code elimination in ThinLTO

Original issue's description:
> Enable ThinLTO and LLD for POSIX LTO by default on Linux.
> 
> Eventually, we will enable LLD on Linux even for regular
> builds, but it's natural to make incremental steps here.
> 
> ThinLTO brings multi-threaded linking for LinkTimeOptimization
> builds, which allows to speed up codegen considerably (up to 4x).
> ThinLTO also manages a cache inside out/<gn-config>/thinlto-cache
> directory, that improves incremental linking as well.
> 
> There's a cache pruning policy that will prevent the cache from
> growing indefinitely. The policy is not yet finalized, and
> complaints / suggestions are welcome.
> 
> BUG=660216,607968
> 
> Review-Url: https://codereview.chromium.org/2831213006
> Cr-Commit-Position: refs/heads/master@{#466732}
> Committed:
https://chromium.googlesource.com/chromium/src/+/7997bbe88aef7eeca37111dcb842...

TBR=dpranke@chromium.org,thakis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660216,607968
==========

to

==========
Revert of Enable ThinLTO and LLD for POSIX LTO by default on Linux. (patchset #4
id:60001 of https://codereview.chromium.org/2831213006/ )

Reason for revert:
Code size increase:
https://chromeperf.appspot.com/report?sid=7826328365affe1842778994c934cbe08c7...

Postmortem is coming. TL;DR: worse dead code elimination in ThinLTO

Original issue's description:
> Enable ThinLTO and LLD for POSIX LTO by default on Linux.
> 
> Eventually, we will enable LLD on Linux even for regular
> builds, but it's natural to make incremental steps here.
> 
> ThinLTO brings multi-threaded linking for LinkTimeOptimization
> builds, which allows to speed up codegen considerably (up to 4x).
> ThinLTO also manages a cache inside out/<gn-config>/thinlto-cache
> directory, that improves incremental linking as well.
> 
> There's a cache pruning policy that will prevent the cache from
> growing indefinitely. The policy is not yet finalized, and
> complaints / suggestions are welcome.
> 
> BUG=660216,607968
> 
> Review-Url: https://codereview.chromium.org/2831213006
> Cr-Commit-Position: refs/heads/master@{#466732}
> Committed:
https://chromium.googlesource.com/chromium/src/+/7997bbe88aef7eeca37111dcb842...

TBR=dpranke@chromium.org,thakis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660216,607968

Review-Url: https://codereview.chromium.org/2842683002
Cr-Commit-Position: refs/heads/master@{#466842}
Committed:
https://chromium.googlesource.com/chromium/src/+/6aee4d67dcc67850c8ec7b9fc181...
==========

[commit-bot: I haz the power, 2017-04-25 00:42:38]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/6aee4d67dcc67850c8ec7b9fc181...

[Dirk Pranke, 2017-04-25 00:43:16]

lgtm