Fix a crash in ChromeActiveDocument::IOleObject_SetClientSite. Check validity of existing document soite before QI for doc host handler.
Fix a crash in ChromeActiveDocument::IOleObject_SetClientSite.
Check validity of existing document soite before QI for
doc host handler.

BUG=37008
TEST=none
TBR=ananta

Review URL: http://codereview.chromium.org/660255

git-svn-id: http://src.chromium.org/svn/trunk/src@40235 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 8472b195557730ff1c30601389d7a4f889dd2e77
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser