[AST] Add method to concatenate AstRawStrings

[AST] Add method to concatenate AstRawStrings

Normally the parser just uses AstConsStrings to concatenate, but some
types require an AstRawString. This patch adds an AstValueFactory
method which produces one from two AstRawStrings.

Committed: https://crrev.com/e68258bd154a756bbf8a84a7edf386da2db05da2
Cr-Commit-Position: refs/heads/master@{#39482}

[bakkot, 2016-09-16 01:40:58]

bakkot@google.com changed reviewers:
+ adamk@chromium.org, littledan@chromium.org

[bakkot, 2016-09-16 01:40:59]

PTAL.

This isn't tested at all, so don't merge quite yet, but I believe it to be
correct and so wanted to give it a chance to get looked at.

[bakkot, 2016-09-16 21:42:17]

This now has a test and a slightly less dumb implementation.

[adamk, 2016-09-16 22:24:38]

lgtm

[bakkot, 2016-09-16 23:16:04]

The CQ bit was checked by bakkot@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-09-16 23:16:15]

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

[bakkot, 2016-09-16 23:33:22]

The CQ bit was unchecked by bakkot@google.com

[bakkot, 2016-09-16 23:33:24]

The CQ bit was checked by bakkot@google.com

[commit-bot: I haz the power, 2016-09-16 23:33:31]

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, 2016-09-16 23:49:20]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-09-16 23:49:48]

Description was changed from

==========
[AST] Add method to concatenate AstRawStrings

Normally the parser just uses AstConsStrings to concatenate, but some
types require an AstRawString. This patch adds an AstValueFactory
method which produces one from two AstRawStrings.
==========

to

==========
[AST] Add method to concatenate AstRawStrings

Normally the parser just uses AstConsStrings to concatenate, but some
types require an AstRawString. This patch adds an AstValueFactory
method which produces one from two AstRawStrings.

Committed: https://crrev.com/e68258bd154a756bbf8a84a7edf386da2db05da2
Cr-Commit-Position: refs/heads/master@{#39482}
==========

[commit-bot: I haz the power, 2016-09-16 23:49:49]

Patchset 2 (id:??) landed as
https://crrev.com/e68258bd154a756bbf8a84a7edf386da2db05da2
Cr-Commit-Position: refs/heads/master@{#39482}