@seanlong thanks for patching, I really appreciate your efforts on improving this code
Could I however ask you to go a bit further? let's do the following:
1) create PackageInstaller class and make all these DoSomethingForTizen functions its methods having simpler names (PackageInstaller::UpdateApplication, PackageInstaller::InstallApplication..)
2) rename the existing PkgInstaller class to 'PackageInstallerHelper' and try to make it to have the similar methods&semantics as PackageInstaller has.
3) Put (!XWalkRunner::GetInstance()->is_running_as_service()) checks inside PackageInstaller methods in order to remove unneeded wrappers from ApplicationService. I think those checks can be just assertions and on Tizen we just should disable "--install/uninstall" xwalk cmd line args handling (this can be done with different patches off course).