message: let onChange set originalEditorState
diff: @@ -346,7 +346,7 @@ export default class MessageComposerInput extends React.Component {
  }
  }
  - onChange = (change: Change) => {
  + onChange = (change: Change, originalEditorState: value) => {
  let editorState = change.value;
  @@ -467,7 +467,7 @@ export default class MessageComposerInput extends React.Component {
  /* Since a modification was made, set originalEditorState to null, since newState is now our original */
  this.setState({
  editorState,
  - originalEditorState: null,
  + originalEditorState: originalEditorState || null
  });
  };
  @@ -1050,11 +1050,7 @@ export default class MessageComposerInput extends React.Component {
  }
  editorState = change.value;
  - this.onChange(change);
  -
  - this.setState({
  - originalEditorState: activeEditorState
  - });
  + this.onChange(change, activeEditorState);
  return true;
  };
  