Fixes possible crash in closing window. The sequence when closing a window ends like:
Fixes possible crash in closing window. The sequence when closing a
window ends like:

~TabStrip
~View
~Tab
~Tab::TabContextMenuContents
~TabStrip::TabContextMenuContents
TabStrip::StopAllHighlighting

This is problematic as StopAllHighlighting references objects whose
destructor has already run. This crashes on Linux, but not on windows
(probably because of different implementation of stl).

I've fixed this by deleting all child views from ~TabStrip so that if
they end up calling into the TabStrip every is still valid.

BUG=none
TEST=create a couple of tabs, bring up the context menu for each,
     close the context menu, close the window and make sure you don't get a
     crash. Be sure and test this on both windows and Chrome OS.

Review URL: http://codereview.chromium.org/505066

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@35151 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,gavinp/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,ropik/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,ropik/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,adobe/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,ropik/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,ropik/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,adobe/chromium,adobe/chromium,yitian134/chromium