Use getSpellCheckLanguages() instead of a setting

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/BasePlatform.ts

@@ -250,6 +250,10 @@ export default abstract class BasePlatform {
 
     setSpellCheckLanguages(preferredLangs: string[]) {}
 
+    getSpellCheckLanguages(): Promise<string[]> | null {
+        return null;
+    }
+
     getAvailableSpellCheckLanguages(): Promise<string[]> | null {
         return null;
     }

src/components/views/settings/tabs/user/GeneralUserSettingsTab.js

@@ -50,7 +50,7 @@ export default class GeneralUserSettingsTab extends React.Component {
 
         this.state = {
             language: languageHandler.getCurrentLanguage(),
-            spellCheckLanguages: SettingsStore.getValue("spell-check-languages", null, false),
+            spellCheckLanguages: [],
             haveIdServer: Boolean(MatrixClientPeg.get().getIdentityServerUrl()),
             serverSupportsSeparateAddAndBind: null,
             idServerHasUnsignedTerms: false,
@@ -87,6 +87,15 @@ export default class GeneralUserSettingsTab extends React.Component {
         this._getThreepidState();
     }
 
+    async componentDidMount() {
+        const plaf = PlatformPeg.get();
+        if (plaf) {
+            this.setState({
+                spellCheckLanguages: await plaf.getSpellCheckLanguages(),
+            });
+        }
+    }
+
     componentWillUnmount() {
         dis.unregister(this.dispatcherRef);
     }