PVS-Studio warning V595 for Chromium

bool ManagedUserService::UserMayLoad(
  const extensions::Extension* extension,
  string16* error) const
{
  if (extension_service &&
      extension_service->GetInstalledExtension(extension->id()))
    return true;

  if (extension) {
    bool was_installed_by_default =
      extension->was_installed_by_default();
    .....
  }
}

This suspicious code was found in Chromium project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'extension' pointer was utilized before it was verified against nullptr. Check lines: 277, 280. managed_user_service.cc 277

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/