Allow BITS downloads of components only in certain cases.

agl@, I need an owner review for the crlset change.

BITS download is broken when the download is hosted by certain serving backends. Until the range support is improved, BITS can be used only in some cases.

For full downloads, everything uses BITS but CRLSet.
For diff downloads, nothing uses BITS

BUG=340450

Review URL: https://codereview.chromium.org/131453006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248946 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed