message: Content in Composer is not lost on unload so it should be fine
  to scare the user thinking they have lost all of their content
  even though when they come back they can cry with joy :D
diff: @@ -43,7 +43,6 @@ export default class MessageComposer extends React.Component {
  this.onToggleMarkdownClicked = this.onToggleMarkdownClicked.bind(this);
  this.onInputStateChanged = this.onInputStateChanged.bind(this);
  this.onEvent = this.onEvent.bind(this);
  - this.onPageUnload = this.onPageUnload.bind(this);
  this.state = {
  autocompleteQuery: '',
  @@ -65,22 +64,12 @@ export default class MessageComposer extends React.Component {
  // marked as encrypted.
  // XXX: fragile as all hell - fixme somehow, perhaps with a dedicated Room.encryption event or something.
  MatrixClientPeg.get().on("event", this.onEvent);
  -
  - window.addEventListener('beforeunload', this.onPageUnload);
  }
  componentWillUnmount() {
  if (MatrixClientPeg.get()) {
  MatrixClientPeg.get().removeListener("event", this.onEvent);
  }
  - window.removeEventListener('beforeunload', this.onPageUnload);
  - }
  -
  - onPageUnload(event) {
  - if (this.messageComposerInput && this.messageComposerInput.isTyping) {
  - return event.returnValue =
  - 'You seem to be typing a message, are you sure you want to quit?';
  - }
  }
  onEvent(event) {
  