Stop using the old-style profile names when using --new-profile-management

Instead use:
- "You" for a single, local profile
- The custom name chosen by the user, if the user renames the profile
- The user's GAIA first name for signed in profiles
- Person %n in all other cases.

This will be used consistently in both by the avatar menu button, and the avatar bubble.

Bonus changes to make this work:
- changed the name and signature of profiles::GetActiveProfileDisplayName to
GetAvatarNameForProfile, to make sure it's not accidentally used
outside of the avatar button related stuff, with baffling results ("Why is the profile name 'You'?)
- the Win avatar button now listens to ProfileInfoCache changes (just like the Mac one does), so that if a new profile is added, the avatar button changes from displaying 'You' to the actual profile name.

BUG=312352

Review URL: https://codereview.chromium.org/171523004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253588 0039d316-1c4b-4281-b951-d872f2087c98
Adds images for the various security states.

R=shess@chromium.org
BUG=

Review URL: https://codereview.chromium.org/174013005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253589 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253589