Fix crashes on SnowLeopard

Dynamically removing layers on SnowLeopard results in crashes the next
time through the run loop. Just leave SnowLeopard windows with layers
for every view once they have been made fullscreen.

This may degrade performance (it does on 10.9, but that's a very
different world from 10.6).

BUG=348328
R=avi@chromium.org

Review URL: https://codereview.chromium.org/185693007/



git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254587 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254587