force model update after composition finishes

src/components/views/rooms/BasicMessageComposer.js

@@ -152,6 +152,9 @@ export default class BasicMessageEditor extends React.Component {
 
     _onCompositionEnd = (event) => {
         this._isIMEComposing = false;
+        // some browsers (chromium) don't fire an input event after ending a composition
+        // so trigger a model update after the composition is done by calling the input handler
+        this._onInput({inputType: "insertCompositionText"});
     }
 
     _onInput = (event) => {