function ClassDeclaration( node, state, clbk ) {
	if ( state.ancestors[ state.ancestors.length-2 ] === state.body ) {
		state.prepend( node, 'global.'+node.id.name+'=' );
	}
	walk.base.ClassDeclaration( node, state, clbk ); // eslint-disable-line new-cap
}
Callback invoked upon encountering a `ClassDeclaration` AST node.

@private
@param {Node} node - AST node
@param {Object} state - state
@param {Function} clbk - callback