Delete downloads after updating observers.
Delete downloads after updating observers.

The download page adds itself as an observer to in-progress
and unconfirmed dangerous downloads, and removes itself when
the download manager indicates its state has changed.

This caused a crash when the downloads were deleted during a
"clear browsing data" operation, since the delete happened
before the download page was notified of a download manager
state change. The download page then attempted to remove itself
from a deleted item.

BUG=9444 (http://crbug.com/9444)

Review URL: http://codereview.chromium.org/56096

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@12874 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser