Rearrange to use existing back icon

src/components/close-button/close-button.jsx

@@ -4,7 +4,7 @@ import classNames from 'classnames';
 
 import styles from './close-button.css';
 import closeIcon from './icon--close.svg';
-import backIcon from './icon--back.svg';
+import backIcon from '../../lib/assets/icon--back.svg';
 
 const CloseButton = props => (
     <div

src/components/modal/modal.jsx

@@ -7,7 +7,7 @@ import Box from '../box/box.jsx';
 import Button from '../button/button.jsx';
 import CloseButton from '../close-button/close-button.jsx';
 
-import placeholderSvg from '../../lib/assets/placeholder.svg';
+import backIcon from '../../lib/assets/icon--back.svg';
 
 import styles from './modal.css';
 
@@ -43,7 +43,7 @@ const ModalComponent = props => (
                     {props.fullScreen ? (
                         <Button
                             className={styles.backButton}
-                            iconSrc={placeholderSvg}
+                            iconSrc={backIcon}
                             onClick={props.onRequestClose}
                         >
                             Back