Use StringView for String::find.

Use StringView for String::find.

This merges all of the StringImpl::find code paths for non-single letter
cases by using StringView.

I also made all of the find overloads match for String and AtomicString.

BUG=615174
Committed: https://crrev.com/54316d7250bc5a6e48ad1161cf6014081b7f7b89
Cr-Commit-Position: refs/heads/master@{#410547}

[esprehn, 2016-08-08 20:50:50]

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

[commit-bot: I haz the power, 2016-08-08 20:51:07]

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

[esprehn, 2016-08-08 21:05:36]

esprehn@chromium.org changed reviewers:
+ haraken@chromium.org, jbroman@chromium.org

[commit-bot: I haz the power, 2016-08-08 21:07:35]

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

[commit-bot: I haz the power, 2016-08-08 21:07:35]

Dry run: Try jobs failed on following builders:
  chromeos_daisy_chromium_compile_only_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_daisy_...)

[jbroman, 2016-08-08 21:18:30]

lgtm, but please be on the lookout for possible perf regressions.

I suspect the compiler won't be smart enough to optimize out the is8Bit branch
even when it's statically known, because the indirection through
StringImpl::empty/empty16Bit will probably defeat the optimizer. But the
difference may not have an impact in reality.

[esprehn, 2016-08-08 21:23:51]

On 2016/08/08 at 21:18:30, jbroman wrote:
> lgtm, but please be on the lookout for possible perf regressions.
> 
> I suspect the compiler won't be smart enough to optimize out the is8Bit branch
even when it's statically known, because the indirection through
StringImpl::empty/empty16Bit will probably defeat the optimizer. But the
difference may not have an impact in reality.

The existing code is less awesome than you think, the overload before was for
LChar*, but almost all callers are using a literal which is a char* not an
LChar*, so they were actually calling:

find(const String& str, ...)

which mean they were doing a malloc for the needle string and then doing the
same work this patch was doing checking is8Bit etc.

This patch should be less work everywhere I think since now we avoid the malloc
+ copy. I'll definitely keep an eye out though. :)

[esprehn, 2016-08-08 23:27:53]

The CQ bit was checked by esprehn@chromium.org

[esprehn, 2016-08-08 23:27:53]

The patchset sent to the CQ was uploaded after l-g-t-m from jbroman@chromium.org
Link to the patchset: https://codereview.chromium.org/2225173002/#ps20001
(title: "Add missing null check.")

[commit-bot: I haz the power, 2016-08-08 23:28:13]

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

[haraken, 2016-08-08 23:32:43]

LGTM

[commit-bot: I haz the power, 2016-08-09 02:41:39]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-08-09 02:45:01]

Description was changed from

==========
Use StringView for String::find.

This merges all of the StringImpl::find code paths for non-single letter
cases by using StringView.

I also made all of the find overloads match for String and AtomicString.

BUG=615174
==========

to

==========
Use StringView for String::find.

This merges all of the StringImpl::find code paths for non-single letter
cases by using StringView.

I also made all of the find overloads match for String and AtomicString.

BUG=615174

Committed: https://crrev.com/54316d7250bc5a6e48ad1161cf6014081b7f7b89
Cr-Commit-Position: refs/heads/master@{#410547}
==========

[commit-bot: I haz the power, 2016-08-09 02:45:02]

Patchset 2 (id:??) landed as
https://crrev.com/54316d7250bc5a6e48ad1161cf6014081b7f7b89
Cr-Commit-Position: refs/heads/master@{#410547}