Move PaginationModel into AppListViewFactoryImpl.

The ability to specify different pagination models for different views is not
very useful and just serves to bloat the interface currently.

Review URL: https://codereview.chromium.org/25728005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226974 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226974