Base structure.
Called to check if a Chrome app menu item should be enabled. Values for |command_id| can be found in the cef_command_ids.h file. Only called for menu items that would be enabled by default. Only used with the Chrome runtime.
Called to check if a Chrome app menu item should be visible. Values for |command_id| can be found in the cef_command_ids.h file. Only called for menu items that would be visible by default. Only used with the Chrome runtime.
Called during browser creation to check if a Chrome page action icon should be visible. Only called for icons that would be visible by default. Only used with the Chrome runtime.
Called during browser creation to check if a Chrome toolbar button should be visible. Only called for buttons that would be visible by default. Only used with the Chrome runtime.
Implement this structure to handle events related to commands. The functions of this structure will be called on the UI thread.