Fixes possible crash in creating Browser. The crash could happen because its possible for the browserwindow to be null when SaveWindowPlacement is invoked (when the browserwindow is initially created). If the SessionService ends up asking the browser for the browserwindow it would get null and crash.
Fixes possible crash in creating Browser. The crash could happen
because its possible for the browserwindow to be null when
SaveWindowPlacement is invoked (when the browserwindow is initially
created). If the SessionService ends up asking the browser for the
browserwindow it would get null and crash.

BUG=4666
TEST=no direct way to test this as its rather random. But make sure
  you don't encounter any problems with session restore.

Review URL: http://codereview.chromium.org/11567

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@5844 0039d316-1c4b-4281-b951-d872f2087c98

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