Widget Customizer: Add pre_update_option filter, replace Options_Transaction

[ocean90]

The plan was to remove Options_Transaction completely, but we can't at least not for the old single widgets.

I'm attaching the patch from #27112 where Options_Transaction is now Option_Update_Capture.
The goal should be, to use Option_Update_Capture only for old single widgets.

Previously reported and resolved wontfix in #13836

[westonruter]

Refresh patch. Conflicts also resolved at ​https://github.com/x-team/wordpress-develop/pull/1/files

[westonruter]

Replace Options_Transaction with option update capturing with methods merged into class WP_Customize_Widgets. Patches, commits, and conflict resolutions also pushed to ​https://github.com/x-team/wordpress-develop/pull/1/files

[ocean90]

Current state: ​https://irclogs.wordpress.org/chanlog.php?channel=wordpress-dev&day=2014-03-26&sort=asc#m819223

[westonruter]

I'll convert the static-flavoured WP_Customize_Widgets into a properly-instantiated class.

[westonruter]

Convert static WP_Customize_Widgets class into instantiated class. Changes also pushed to GitHub: ​https://github.com/x-team/wordpress-develop/pull/1/files

[westonruter]

For the changes between 27504.2.patch and 27504.3.patch, see: ​https://github.com/x-team/wordpress-develop/commit/223004ae1130857525b64f2706f97c417a3059df

[ocean90]

In 27815:

Introduce pre_update_option filter.

Filter is available in update_option() and allows to filter any option before its value is (maybe) serialized and updated.

see #27504.
props westonruter.

[ocean90]

In 27816:

Widget Customizer: Convert static WP_Customize_Widgets class into instantiated class and merge Options_Transaction into WP_Customize_Widgets.

see #27504.
props westonruter.

[nacin]

[27816] is great. Really solid. Closing as fixed, great work both.