[Mac] Custom skin for the new avatar button

- add the new resources to the grd file
- while we're at it, fix the win resources which were included in everything :(
- apply a nine-patch to the button
- increase the width of the fullscreen icon by 2 pixels so that the avatar button
perfectly aligns with the omnibox. (see screenshot)

Screenshots:
https://drive.google.com/folderview?id=0B1B1Up4p2NRMX2haRFo5cm9HbTg&usp=sharing

BUG=305041

Review URL: https://codereview.chromium.org/154583003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250392 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250392