Fix a memory leak in the download shelf.
Fix a memory leak in the download shelf.

Windows doesn't explicitly delete the DownloadItemView objects because the View destructor deletes child views automatically.

BUG=10739

Review URL: http://codereview.chromium.org/88044

git-svn-id: http://src.chromium.org/svn/trunk/src@14131 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 9dd3a42b85e1d2683ba0039b84a89beaa251f493
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