As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
return widget()->IsFullscreen();
}
void NativeWindowViews::SetBounds(const gfx::Rect& bounds, bool animate) {
#if defined(OS_WIN) || defined(OS_LINUX)
  
  
  if (!resizable_) {
    SetMaximumSize(bounds.size());
    SetMinimumSize(bounds.size());
  }
#endif
  widget()->SetBounds(bounds);
}
gfx::Rect NativeWindowViews::GetBounds() {
#if defined(OS_WIN)
  if (IsMinimized())
    return widget()->GetRestoredBounds();
#endif
  return widget()->GetWindowBoundsInScreen();
}
gfx::Rect NativeWindowViews::GetContentBounds() {