Fix crash in delayed tab resizing. If the Resize Relayout code is called after the last tab has been closed but before the window is destroyed (this whole process is very async) there are zero tabs in the layout and as a result GetTabAt(0) will crash.
Fix crash in delayed tab resizing. If the Resize Relayout code is called after the last tab has been closed but before the window is destroyed (this whole process is very async) there are zero tabs in the layout and as a result GetTabAt(0) will crash.

http://crbug.com/14603
TEST=none

Review URL: http://codereview.chromium.org/150064

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@19557 0039d316-1c4b-4281-b951-d872f2087c98

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