Use emptyString() for String fields in SecurityOrigin

Use emptyString() for String fields in SecurityOrigin

This prevents needlessly creating empty StringImpls.

BUG=348655
Committed: https://crrev.com/cf43e1d4dc7f75e04e08fa28339d305a56133166
Cr-Commit-Position: refs/heads/master@{#426498}

[Charlie Harrison, 2016-10-19 20:55:50]

The CQ bit was checked by csharrison@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-19 20:56:18]

Dry run: 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, 2016-10-19 22:38:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-19 22:38:49]

Dry run: This issue passed the CQ dry run.

[Charlie Harrison, 2016-10-19 23:32:36]

csharrison@chromium.org changed reviewers:
+ tsepez@chromium.org

[Charlie Harrison, 2016-10-19 23:32:36]

tsepez, WDYT about this simple patch?

[Tom Sepez, 2016-10-20 16:34:58]

lgtm

[Charlie Harrison, 2016-10-20 16:35:22]

The CQ bit was checked by csharrison@chromium.org

[commit-bot: I haz the power, 2016-10-20 16:35:50]

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, 2016-10-20 16:40:36]

Committed patchset #1 (id:1)

[esprehn, 2016-10-20 20:52:01]

esprehn@chromium.org changed reviewers:
+ esprehn@chromium.org

[esprehn, 2016-10-20 20:52:01]

Note that this wasn't actually creating empty StringImpl's, StringImpl::create
already detects empty strings and returns the same thing:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/wtf/text/Strin...

This saves a small amount of ref churn I guess?

[Charlie Harrison, 2016-10-20 21:01:48]

On 2016/10/20 20:52:01, esprehn wrote:
> Note that this wasn't actually creating empty StringImpl's, StringImpl::create
> already detects empty strings and returns the same thing:
>
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/wtf/text/Strin...
> 
> This saves a small amount of ref churn I guess?

Ah, thanks for the clarification, you're absolutely right. I guess we also save
a cheap strlen and release assert? Nothing too exciting, unfortunately :P

[commit-bot: I haz the power, 2016-10-21 13:18:58]

Description was changed from

==========
Use emptyString() for String fields in SecurityOrigin

This prevents needlessly creating empty StringImpls.

BUG=348655
==========

to

==========
Use emptyString() for String fields in SecurityOrigin

This prevents needlessly creating empty StringImpls.

BUG=348655

Committed: https://crrev.com/cf43e1d4dc7f75e04e08fa28339d305a56133166
Cr-Commit-Position: refs/heads/master@{#426498}
==========

[commit-bot: I haz the power, 2016-10-21 13:18:59]

Patchset 1 (id:??) landed as
https://crrev.com/cf43e1d4dc7f75e04e08fa28339d305a56133166
Cr-Commit-Position: refs/heads/master@{#426498}