A class for managing the editor toolbar. Acts as a bridge between a goog.editor.Field and a goog.ui.Toolbar.

The toolbar argument must be an instance of goog.ui.Toolbar or a subclass. This class doesn't care how the toolbar was created. As long as one or more controls hosted in the toolbar have IDs that match built-in goog.editor.Commands, they will function as expected. It is the caller's responsibility to ensure that the toolbar is already rendered or that it decorates an existing element.