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This change separates the logic into two different classes. It also
- Brings back a bounce animation when there is only one window that was
lost at some point in the past.
- Removes the minimized animation if there is only one window while alt tabbing.

Basically I brought back from the past two classes,
WindowCycleController and WindowCycleList and adapted them
to work with the new codebase. Also, I moved some tests from
WindowSelectorUnittest to WindowCycleControllerUnittest, and 
removed the ones that are now irrelevant. 

Finally, we are also dropping support for alt-tabbing while
in overview mode in favour of cancelling the latter.
BUG=365786
TEST=none

Review URL: https://codereview.chromium.org/260883005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269997 0039d316-1c4b-4281-b951-d872f2087c98