Replace the DownloadFileManager with direct ownership 
of DownloadFileImpl by DownloadItemImpl.

BUG=123998
R=benjhayden@chromium.org


Review URL: https://chromiumcodereview.appspot.com/10799005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151351 0039d316-1c4b-4281-b951-d872f2087c98
35 files changed