Remove ui_resources target from ui.gyp.

Blink was already updated to reference the target from
ui/resources/ui_resources.gyp in
https://src.chromium.org/viewvc/blink?view=rev&revision=162387,
so now we can remove this target from ui.gyp.

BUG=299841
TEST=None
R=ben@chromium.org,jochen@chromium.org
TBR=ben

Review URL: https://codereview.chromium.org/84043003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237348 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237348
[Downloads] Don't store or use validators unless they are strong.

ETag and Last-Modified headers shouldn't be used unless they imply
byte-wise equivalence. While RFC 2616 states that a client 'MAY' use them
anyway, we are going to be conservative and only use them if they are
strong.

BUG=7648

Review URL: https://codereview.chromium.org/67883007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237349 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237349