aura: Implement app list M19 mock.
- Make AppListModel flat, i.e. remove AppListItemGroupModel and its view;
- Move BuildAppListModel from ShellDelegate into AppListViewDelegate;
- Make AppListModelBuilder ready to support simple query;
- Make AppListItemView based on CustomButton and get rid of its listener
interface since we can use ButtonListener for that now;
- Update UI based on M19 mock:
- AppListItemView show label on its right instead of bottom;
- AppListItemView has a mouse hover effect now;
- AppListModelView show AppListItemView tiles alphabetically from top to
bottom instead of from left to right;
- AppListView to occupy full screen include area behind the launcher;
- AppListView to have a 0.4 black shade;
BUG=98308
TEST=Verify applist should look like M19 mock.
Review URL: https://chromiumcodereview.appspot.com/
9559005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124661 0039d316-1c4b-4281-b951-d872f2087c98