[Theming] Remove support for core Component foreground / background colors

[kirill-grouchnikov]

JComponent.setForeground(Color) and JComponent.setBackground(Color) APIs have traditionally been awkward to support across various Radiance theming features, and with the recent changes in the Radiance color APIs, it is time to remove support for these core Swing features.

Setting a single background or a single foreground color for a component does not scale well with how Radiance handles different component states - rollover, selected, pressed, armed, determinate, mixed. For a while now, Radiance has supported the notion of colorization - using the custom background / foreground colors to "mix" them into the current skin, with the colorization factor APIs in global and component parent chain scopes.

The most recent addition of ComponentScope.setContainerColorTokensOverlay API in Radiance 8.5 should address a variety of app use cases to "mark" a certain element with an "off skin" color - be it one of the system color tokens added in Radiance 8.0 (info, warning, error, success), or a completely custom color token configuration.

Marking this as breaking change, since this will be removing the colorization factor APIs, and also removing the "visual" support for background / foreground component APIs.

[kirill-grouchnikov]

Note:

• Containers such as JPanel, JRootPane, JOptionPane, JScrollPane and JDesktopPane will still support the background color configured on them during painting.
• This also applies to renderer-based containers such as JList, JTree and JTable, including their renderers.
• This also applies to the overall background drawn for components such as JLabel, JCheckBox and others where JComponent.setBackground applies to the overall rectangular area occupied by that component.

This specific issue will remove the application of foreground and background color to components such as JButton, and to the "real" visuals of components such as JCheckBox (its mark box and its text).