[add button to tinymce]

functions.php

<?php
add_action( 'after_setup_theme', 'mythemeslug_theme_setup' );

if ( ! function_exists( 'mythemeslug_theme_setup' ) ) {
	function mythemeslug_theme_setup(){
		/********* Registers an editor stylesheet for the theme ***********/
		add_action( 'admin_init', 'mythemeslug_theme_add_editor_styles' );
		/********* TinyMCE Buttons ***********/
		add_action( 'init', 'mythemeslug_buttons' );
	}
}

/********* Registers an editor stylesheet for the theme ***********/
if ( ! function_exists( 'mythemeslug_theme_add_editor_styles' ) ) {
	function mythemeslug_theme_add_editor_styles() {
	    // add_editor_style( 'custom-editor-style.css' );
	}
}

/********* TinyMCE Buttons ***********/
if ( ! function_exists( 'mythemeslug_buttons' ) ) {
	function mythemeslug_buttons() {
		if ( ! current_user_can( 'edit_posts' ) && ! current_user_can( 'edit_pages' ) ) {
	        return;
	    }

	    if ( get_user_option( 'rich_editing' ) !== 'true' ) {
	        return;
	    }

	    add_filter( 'mce_external_plugins', 'mythemeslug_add_buttons' );
	    add_filter( 'mce_buttons', 'mythemeslug_register_buttons' );
	}
}

if ( ! function_exists( 'mythemeslug_add_buttons' ) ) {
	function mythemeslug_add_buttons( $plugin_array ) {
	    $plugin_array['columns'] = get_template_directory_uri().'/js/tinymce_buttons.js';
	    return $plugin_array;
	}
}

if ( ! function_exists( 'mythemeslug_register_buttons' ) ) {
	function mythemeslug_register_buttons( $buttons ) {
	    array_push( $buttons, 'columns' );
	    return $buttons;
	}
}

function bmessage( $atts, $content ){
    $title = (isset($atts['title'])) ? $atts['title'] : '';
    $color = (isset($atts['color'])) ? $atts['color'] : 'green';


    $output = '<div class="bMessage bMessage__'.$color.'">';
        if($title) $output .= '<div class="bMessage__title subject">'.$title.'</div>';
        $output .= '<div class="bMessage__content wysiwyg">'.$content.'</div>';
    $output .= '</div>';
    return $output;
}
add_shortcode('message', 'bmessage');

tinymce_buttons.js

(function() {
    tinymce.PluginManager.add( 'columns', function( editor, url ) {
        function addHtmlShorcode(text, color) {
            var output = '';
            var open_column = '[message color="'+color+'" title="Заголовок"]';
            var close_column = '[/message]';

            output = open_column + text + close_column;

            return output;
        }
        // Add Button to Visual Editor Toolbar
        editor.addButton('columns', {
            text: 'Блок «Сообщение»',
              icon: false,
              type: 'menubutton',
              menu: [
                    {
                        text: 'Зеленый',
                        onclick: function() {
                            var selected_text = editor.selection.getContent({'format': 'html'});
                            if ( selected_text.length === 0 ) {
                                alert( 'Нужно выделить какой то текст' );
                                return;
                            }
                            editor.execCommand('mceReplaceContent', false, addHtmlShorcode(selected_text, 'green'));
                        }
                     }, {
                        text: 'Жёлтый',
                        onclick: function() {
                            var selected_text = editor.selection.getContent({'format': 'html'});
                            if ( selected_text.length === 0 ) {
                                alert( 'Нужно выделить какой то текст' );
                                return;
                            }
                            editor.execCommand('mceReplaceContent', false, addHtmlShorcode(selected_text, 'yellow'));
                        }
                     }, {
                        text: 'Красный',
                        onclick: function() {
                            var selected_text = editor.selection.getContent({'format': 'html'});
                            if ( selected_text.length === 0 ) {
                                alert( 'Нужно выделить какой то текст' );
                                return;
                            }
                            editor.execCommand('mceReplaceContent', false, addHtmlShorcode(selected_text, 'red'));
                        }
                    }
                ]
        });
    });

})();