Return promise so that project can handle rejection (#663)

Author: markholland

src/DocumentView/DocumentView.tsx

@@ -948,7 +948,7 @@ export class DocumentView extends PureComponent<DocumentViewProps, any> {
  setColorPostProcessMode = (colorPostProcessMode: Config.ColorPostProcessMode): Promise<void> => {
  const tag = findNodeHandle(this._viewerRef);
  if (tag != null) {
- DocumentViewManager.setColorPostProcessMode(tag, colorPostProcessMode);
+ return DocumentViewManager.setColorPostProcessMode(tag, colorPostProcessMode);
  }
  return Promise.resolve();
  }