message: If the preview window becomes available later, then init it later
  * E.g. on android this can happen if we started the replay while the
  replay apk wasn't in the foreground, but then it gets raised later.
diff: @@ -1860,7 +1860,7 @@ const DrawcallDescription *ReplayProxy::FindDraw(const rdcarray<DrawcallDescript
  void ReplayProxy::InitPreviewWindow()
  {
  - if(m_Replay && m_PreviewWindow)
  + if(m_Replay && m_PreviewWindow && m_PreviewOutput == 0)
  {
  WindowingData data = m_PreviewWindow(true, m_Replay->GetSupportedWindowSystems());
  if(data.system != WindowingSystem::Unknown)
  @@ -1876,11 +1876,14 @@ void ReplayProxy::ShutdownPreviewWindow()
  {
  m_Replay->DestroyOutputWindow(m_PreviewOutput);
  m_PreviewWindow(false, {});
  + m_PreviewOutput = 0;
  }
  }
  void ReplayProxy::RefreshPreviewWindow()
  {
  + InitPreviewWindow();
  +
  if(m_Replay && m_PreviewOutput)
  {
  m_Replay->BindOutputWindow(m_PreviewOutput, false);
  