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: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@14131 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