Add new first-time tutorial (#9531)

* Prepare to load onboarding as a full page

* Update the first-time introduction

* Improve responsive design

* Replace speech bubble with logo

* Increase text size and reword first paragraph

app/javascript/mastodon/containers/mastodon.js

@@ -1,11 +1,12 @@
 import React from 'react';
-import { Provider } from 'react-redux';
+import { Provider, connect } from 'react-redux';
 import PropTypes from 'prop-types';
 import configureStore from '../store/configureStore';
-import { showOnboardingOnce } from '../actions/onboarding';
+import { INTRODUCTION_VERSION } from '../actions/onboarding';
 import { BrowserRouter, Route } from 'react-router-dom';
 import { ScrollContext } from 'react-router-scroll-4';
 import UI from '../features/ui';
+import Introduction from '../features/introduction';
 import { fetchCustomEmojis } from '../actions/custom_emojis';
 import { hydrateStore } from '../actions/store';
 import { connectUserStream } from '../actions/streaming';
@@ -18,11 +19,39 @@ addLocaleData(localeData);
 
 export const store = configureStore();
 const hydrateAction = hydrateStore(initialState);
-store.dispatch(hydrateAction);
 
-// load custom emojis
+store.dispatch(hydrateAction);
 store.dispatch(fetchCustomEmojis());
 
+const mapStateToProps = state => ({
+  showIntroduction: state.getIn(['settings', 'introductionVersion'], 0) < INTRODUCTION_VERSION,
+});
+
+@connect(mapStateToProps)
+class MastodonMount extends React.PureComponent {
+
+  static propTypes = {
+    showIntroduction: PropTypes.bool,
+  };
+
+  render () {
+    const { showIntroduction } = this.props;
+
+    if (showIntroduction) {
+      return <Introduction />;
+    }
+
+    return (
+      <BrowserRouter basename='/web'>
+        <ScrollContext>
+          <Route path='/' component={UI} />
+        </ScrollContext>
+      </BrowserRouter>
+    );
+  }
+
+}
+
 export default class Mastodon extends React.PureComponent {
 
   static propTypes = {
@@ -31,14 +60,6 @@ export default class Mastodon extends React.PureComponent {
 
   componentDidMount() {
     this.disconnect = store.dispatch(connectUserStream());
-
-    // Desktop notifications
-    // Ask after 1 minute
-    if (typeof window.Notification !== 'undefined' && Notification.permission === 'default') {
-      window.setTimeout(() => Notification.requestPermission(), 60 * 1000);
-    }
-
-    store.dispatch(showOnboardingOnce());
   }
 
   componentWillUnmount () {
@@ -54,11 +75,7 @@ export default class Mastodon extends React.PureComponent {
     return (
       <IntlProvider locale={locale} messages={messages}>
         <Provider store={store}>
-          <BrowserRouter basename='/web'>
-            <ScrollContext>
-              <Route path='/' component={UI} />
-            </ScrollContext>
-          </BrowserRouter>
+          <MastodonMount />
         </Provider>
       </IntlProvider>
     );