Remove the power button for Windows Ash try bubble.

This leaves the date and the |?| in the bubble.

TBR=sadrul
BUG=227247
TEST=power button not seen

Review URL: https://codereview.chromium.org/28453003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229712 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229712