Introduce IsGraphemeBreak function.

Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs.

BUG=594923
Committed: https://crrev.com/376ec7f5a84c0e2f03f813310450c375991f8591
Cr-Commit-Position: refs/heads/master@{#384852}

[Seigo Nonaka, 2016-04-03 19:13:08]

Description was changed from

==========
Introduce IsGraphemeBreak function.

BUG=
==========

to

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production.

BUG=594923
==========

[Seigo Nonaka, 2016-04-03 19:17:10]

Patchset #1 (id:1) has been deleted

[Seigo Nonaka, 2016-04-03 19:18:40]

nona@chromium.org changed reviewers:
+ yosin@chromium.org

[Seigo Nonaka, 2016-04-03 19:18:40]

Hi Yoshi-san,

I'd like to split https://codereview.chromium.org/1833413002/ into four.
This is the first patch.

Could you kindly take a look?

Thank you.

[yosin_UTC9, 2016-04-04 03:49:15]

yosin@chromium.org changed reviewers:
+ tkent@chromium.org

[yosin_UTC9, 2016-04-04 03:49:16]

lgtm

+tkent@ for core OWNERS review

[tkent, 2016-04-04 04:01:10]

> IsGraphemeBreak function is compiled and tested but not used on
> production.

So, what's the purpose of this CL?

[Seigo Nonaka, 2016-04-04 04:09:41]

Description was changed from

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production.

BUG=594923
==========

to

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs. 

BUG=594923
==========

[Seigo Nonaka, 2016-04-04 04:14:33]

I'm sorry for providing few background.

This is a part of large CLs: https://codereview.chromium.org/1833413002/
I'd like to split it into four since it could be a super heavy review if I send
them at the same time.
This function will be used by two classes: BackwardGraphemeBoundaryStateMachine
and ForwardGraphemeBoundaryStateMachine. So I'd like to introduce this function
first.

Followings are subsequent CLs:

Introduce backward movement logic:
https://codereview.chromium.org/1855813002/

Introduce forward movement logic:
https://codereview.chromium.org/1857633002/

Use our own implementation instead of ICU:
https://codereview.chromium.org/1853033002/

If submitting temporary unused classes doesn't make sense to you, I'm happy to
upload all-in-one patch once yosi-san reviewed my all subsequent patches.

Thank you.

[tkent, 2016-04-04 04:24:19]

lgtm

On 2016/04/04 at 04:14:33, nona wrote:
> If submitting temporary unused classes doesn't make sense to you, I'm happy to
upload all-in-one patch once yosi-san reviewed my all subsequent patches.

Please do not send the all-in-one patch, and please do not forget to add the
context to the CL description.

[Seigo Nonaka, 2016-04-04 05:03:22]

On 2016/04/04 04:24:19, tkent wrote:
> lgtm
> 
> On 2016/04/04 at 04:14:33, nona wrote:
> > If submitting temporary unused classes doesn't make sense to you, I'm happy
to
> upload all-in-one patch once yosi-san reviewed my all subsequent patches.
> 
> Please do not send the all-in-one patch, and please do not forget to add the
> context to the CL description.

Sure, thank you for your quick review and I'm sorry for forgetting adding
context.

Submitting...

[Seigo Nonaka, 2016-04-04 05:03:27]

The CQ bit was checked by nona@chromium.org

[commit-bot: I haz the power, 2016-04-04 05:03:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1856603002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1856603002/20001

[commit-bot: I haz the power, 2016-04-04 06:02:43]

Description was changed from

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs. 

BUG=594923
==========

to

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs. 

BUG=594923
==========

[commit-bot: I haz the power, 2016-04-04 06:02:44]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-04-04 06:05:37]

Description was changed from

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs. 

BUG=594923
==========

to

==========
Introduce IsGraphemeBreak function.

Followings are differences from the previous grapheme breaker:
- Follows latest(including proposed) grapheme breaker spec:
  Unicode Standard Annex #29 http://www.unicode.org/reports/tr29

- Removed Tamil exception rule from Indic syllable composition.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=15790
  Neither bug nor change description doesn't mention about Tamil
  exception but latest Unicode standards doesn't have exception.

- Revive Rule GB9b rule: don't break after Prepend property.
  Introduced by https://bugs.webkit.org/show_bug.cgi?id=24342
  It is safe to revive this rule since Thai characters no longer have
  Prepend property since Unicode 6.1.
  Note that there are no character having Prepend property until
  Unicode 9.0 after Unicode 6.1

IsGraphemeBreak function is compiled and tested but not used on
production. This function is used by subsequent CLs.

BUG=594923

Committed: https://crrev.com/376ec7f5a84c0e2f03f813310450c375991f8591
Cr-Commit-Position: refs/heads/master@{#384852}
==========

[commit-bot: I haz the power, 2016-04-04 06:05:39]

Patchset 1 (id:??) landed as
https://crrev.com/376ec7f5a84c0e2f03f813310450c375991f8591
Cr-Commit-Position: refs/heads/master@{#384852}