Add cancel button to updater

src/browser/components/UpdaterPage.jsx

@@ -55,6 +55,11 @@ function UpdaterPage(props) {
             now={props.progress}
             label={`${props.progress}%`}
           />
+          <div className='pull-right'>
+            <Button
+              onClick={props.onClickCancel}
+            >{'Cancel'}</Button>
+          </div>
         </Navbar> :
         <Navbar
           className='UpdaterPage-footer'
@@ -93,6 +98,7 @@ UpdaterPage.propTypes = {
   onClickReleaseNotes: propTypes.func.isRequired,
   onClickRemind: propTypes.func.isRequired,
   onClickSkip: propTypes.func.isRequired,
+  onClickCancel: propTypes.func.isRequired,
 };
 
 export default UpdaterPage;

src/browser/components/UpdaterPage/UpdaterPage.stories.jsx

@@ -48,5 +48,6 @@ storiesOf('UpdaterPage', module).
       appName={appName}
       isDownloading={true}
       progress={0}
+      onClickCancel={action('clicked cancel')}
     />
   ));

src/browser/updater.jsx

@@ -53,6 +53,9 @@ class UpdaterPageContainer extends React.Component {
         onClickDownload={() => {
           ipcRenderer.send('click-download');
         }}
+        onClickCancel={() => {
+          ipcRenderer.send('click-cancel');
+        }}
       />
     );
   }