Reland of clang/win: Enable -Wunused-value completely.

Reland of clang/win: Enable -Wunused-value completely. (patchset #1 id:1 of https://codereview.chromium.org/1501153002/ )

Reason for revert:
This might now work in release builds too.

Original issue's description:
> Revert of clang/win: Enable -Wunused-value completely. (patchset #3 id:40001 of https://codereview.chromium.org/1500783002/ )
>
> Reason for revert:
> This works in debug builds but not in release builds yet.
>
> Original issue's description:
> > clang/win: Enable -Wunused-value completely.
> >
> > BUG=505318
> > NOTRY=true
> >
> > Committed: https://crrev.com/b10a7ada601a07866d50cd13c6af4605e316152e
> > Cr-Commit-Position: refs/heads/master@{#363327}
>
> TBR=hans@chromium.org,wfh@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=505318
>
> Committed: https://crrev.com/9f1715d0cd8bb5c2bcfd00c55aff80e3fb0b7caf
> Cr-Commit-Position: refs/heads/master@{#363331}

TBR=hans@chromium.org,wfh@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=505318
Committed: https://crrev.com/1ecda6b500dbf76343bceace2ff3c8f60132f4ba
Cr-Commit-Position: refs/heads/master@{#363618}

[Nico, 2015-12-07 22:47:56]

Created Reland of clang/win: Enable -Wunused-value completely.

[commit-bot: I haz the power, 2015-12-07 22:51:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1507113002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1507113002/1

[commit-bot: I haz the power, 2015-12-07 22:57:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-07 22:58:52]

Description was changed from

==========
Reland of clang/win: Enable -Wunused-value completely. (patchset #1 id:1 of
https://codereview.chromium.org/1501153002/ )

Reason for revert:
This might now work in release builds too.

Original issue's description:
> Revert of clang/win: Enable -Wunused-value completely. (patchset #3 id:40001
of https://codereview.chromium.org/1500783002/ )
> 
> Reason for revert:
> This works in debug builds but not in release builds yet.
> 
> Original issue's description:
> > clang/win: Enable -Wunused-value completely.
> >
> > BUG=505318
> > NOTRY=true
> >
> > Committed: https://crrev.com/b10a7ada601a07866d50cd13c6af4605e316152e
> > Cr-Commit-Position: refs/heads/master@{#363327}
> 
> TBR=hans@chromium.org,wfh@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=505318
> 
> Committed: https://crrev.com/9f1715d0cd8bb5c2bcfd00c55aff80e3fb0b7caf
> Cr-Commit-Position: refs/heads/master@{#363331}

TBR=hans@chromium.org,wfh@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=505318
==========

to

==========
Reland of clang/win: Enable -Wunused-value completely. (patchset #1 id:1 of
https://codereview.chromium.org/1501153002/ )

Reason for revert:
This might now work in release builds too.

Original issue's description:
> Revert of clang/win: Enable -Wunused-value completely. (patchset #3 id:40001
of https://codereview.chromium.org/1500783002/ )
>
> Reason for revert:
> This works in debug builds but not in release builds yet.
>
> Original issue's description:
> > clang/win: Enable -Wunused-value completely.
> >
> > BUG=505318
> > NOTRY=true
> >
> > Committed: https://crrev.com/b10a7ada601a07866d50cd13c6af4605e316152e
> > Cr-Commit-Position: refs/heads/master@{#363327}
>
> TBR=hans@chromium.org,wfh@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=505318
>
> Committed: https://crrev.com/9f1715d0cd8bb5c2bcfd00c55aff80e3fb0b7caf
> Cr-Commit-Position: refs/heads/master@{#363331}

TBR=hans@chromium.org,wfh@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=505318

Committed: https://crrev.com/1ecda6b500dbf76343bceace2ff3c8f60132f4ba
Cr-Commit-Position: refs/heads/master@{#363618}
==========

[commit-bot: I haz the power, 2015-12-07 22:58:53]

Patchset 1 (id:??) landed as
https://crrev.com/1ecda6b500dbf76343bceace2ff3c8f60132f4ba
Cr-Commit-Position: refs/heads/master@{#363618}