Fix wallpaper change to a random one when user first click "set wallpaper".

Fix wallpaper change to a random one when user first click "set wallpaper" or login 

BUG=119973, 119971
TEST=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=128817

[bshe, 2012-03-25 01:59:26]

Hi Ben.

Could you please take a look at this CL?

Basically Emmanuel's change got reverted here:
https://chromiumcodereview.appspot.com/9835080
which cause these two regression (119973, 119971). 

I found the reason for linux_chromeos crash and have sent try jobs to verify.
Also, I renamed two functions and removed some duplicated code in these
functions.

Thanks!

[Ben Goodger (Google), 2012-03-25 06:44:56]

lgtm

[Nikita (slow), 2012-03-25 21:24:08]

Please fix in a followup CL.

https://chromiumcodereview.appspot.com/9839098/diff/7014/chrome/browser/chrom...
File chrome/browser/chromeos/login/user_manager_impl.cc (right):

https://chromiumcodereview.appspot.com/9839098/diff/7014/chrome/browser/chrom...
chrome/browser/chromeos/login/user_manager_impl.cc:915: if (IsLoggedInAsGuest()
|| !IsUserLoggedIn())
+ IsCurrentUserEphemeral()

In fact you should remove IsLoggedInAsGuest() and add only

if (IsCurrentUserEphemeral() || !IsUserLoggedIn())

IsCurrentUserEphemeral will be true for Demo/Guest/normal users when Ephemeral
policy is enabled / stub user.

Obviously this will block testing change of wallpaper on desktop (where stub
user is normally used) but that should be fixed separately.

https://chromiumcodereview.appspot.com/9839098/diff/7014/chrome/browser/chrom...
chrome/browser/chromeos/login/user_manager_impl.cc:938: if (IsLoggedInAsGuest()
|| !IsUserLoggedIn())
Change IsLoggedInAsGuest() to IsCurrentUserEphemeral() so that ephemeral and
demo users are handled too.

If ephemeral user policy is enabed - no changes should be made to LocalState as
user home will be removed on sign out. All changes should reside in memory.
Demo user / guest user is a variant of ephemeral users.