Make message_names.cc build 10-30x faster.

Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502
Committed: https://crrev.com/7928cc2c14f71116bce5bd74d6c081be292082c8
Cr-Commit-Position: refs/heads/master@{#409852}

[Nico, 2016-08-04 18:10:42]

thakis@chromium.org changed reviewers:
+ inferno@chromium.org, mbarbella@chromium.org

[Nico, 2016-08-04 18:10:42]

First to stamp wins!

[Martin Barbella, 2016-08-04 18:12:19]

lgtm, thanks for investigating and fixing this.

[inferno, 2016-08-04 18:12:48]

lgtm

[Nico, 2016-08-04 18:14:09]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2016-08-04 18:14:51]

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

[Nico, 2016-08-04 18:17:28]

Description was changed from

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
happens to work around a clang bug that causes very slow compile times -- see
the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10minutes.

BUG=630502
==========

to

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10minutes.

BUG=630502
==========

[Nico, 2016-08-04 18:17:48]

Description was changed from

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10minutes.

BUG=630502
==========

to

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502
==========

[commit-bot: I haz the power, 2016-08-04 18:52:07]

Description was changed from

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502
==========

to

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502
==========

[commit-bot: I haz the power, 2016-08-04 18:52:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-04 18:55:21]

Description was changed from

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502
==========

to

==========
Make message_names.cc build 6-30x faster.

MessageNames uses two std::map<>s where std::unordered_map<>s suffice.  Changing
this also happens to work around a clang bug that causes very slow
compile times -- see the linked bug and also http://llvm.org/PR28820

On my laptop, the file now builds in 10s instead of 67s without debug info and
in 20s instead of 10m (!) with debug info.

BUG=630502

Committed: https://crrev.com/7928cc2c14f71116bce5bd74d6c081be292082c8
Cr-Commit-Position: refs/heads/master@{#409852}
==========

[commit-bot: I haz the power, 2016-08-04 18:55:22]

Patchset 1 (id:??) landed as
https://crrev.com/7928cc2c14f71116bce5bd74d6c081be292082c8
Cr-Commit-Position: refs/heads/master@{#409852}