Remove color formatting and sanitization functions from class-wp-customize-manager.php

[westonruter]

There are three global functions defined in class-wp-customize-manager.php which are used for sanitization of settings:

• sanitize_hex_color
• sanitize_hex_color_no_hash
• maybe_hash_hex_color

Defining these functions here can be problematic. When working with a theme recently, it defined these functions “pluggably” in functions.php, wrapping each in a if( ! function_exists() ) check. In a plugin I then wanted to boot up the Customizer Manager at after_setup_theme which then resulted in a fatal error because these functions are not defined “pluggably” in class-wp-customize-manager.php. This isn't the appropriate place for them anyway. Either they should be changed into static methods, or they should be moved some place like formatting.php.

Per @drew in Slack:

Any arguments against moving sanitize_hex_color(), sanitize_hex_color_no_hash(), and maybe_hash_hex_color() out of class-wp-customize-manager.php? I recognize why they're in there but they seem strangely out of place in a Customizer file.

​https://wordpress.slack.com/archives/core/p1424851277006371

[ocean90]

Duplicate of #27583.