[Sync] Rename ModelEnumSet to ModelTypeSet

[Sync] Rename ModelEnumSet to ModelTypeSet

Now that the old ModelTypeSet and ModelTypeBitSet are gone, we can rename
ModelEnumSet to ModelTypeSet.  Conveniently, they're the same number
of characters, so this is just a straight rename.  Command:

git grep -l ModelEnumSet | xargs sed -i '' -e 's/ModelEnumSet/ModelTypeSet/g'

BUG=79970
TEST=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=114149

[akalin, 2011-12-12 22:43:41]

+zea for review

All changes were completely mechanical (via grep/sed).

[Nicolas Zea, 2011-12-13 01:29:54]

lgtm