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1) Moving mouse to left screen edge causes the expanded overflow panels to shrink back.
2) Overflow panel is brought to normal area cannot be dragged correctly.

BUG=106434
TEST=Enable overflow test plus manual test by moving mouse to left screen edge or clicking on overflow panel

Review URL: http://codereview.chromium.org/8802021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113053 0039d316-1c4b-4281-b951-d872f2087c98