[login_manager] throw the switch to in-chrome authentication

This CL begins obsoleting pam_google.  Instead of execing a setuid helper binary
from within chrome that loads pam_google to do authentication, chrome
talks to ClientLogin itself, and then does some other HTTP requests to fetch the
user's google accounts cookies.

BUG=314

TEST=ensure you've got this patch; try logging in.  Also, ran desktopui_DoLogin, login_CryptohomeMounted, login_CryptohomeUnmounted, etc.

Review URL: http://codereview.chromium.org/1640006
1 file changed