Fix bug where we were not displaying icons in the management
UI for disabled extensions.

Also, desaturate the icons of disabled extensions to make them
look more disabledy.

BUG=25963
TEST=On the extensions page, disable an extension, then press
reload. You should see a greyscale version of the icon.

Review URL: http://codereview.chromium.org/360039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31139 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed