GitLab

 Unscaled image only contains 1.0f image and used when it is the client responsibility to scale the image properly (Wallpaper for example)

 This is required for https://codereview.chromium.org/263253003/

BUG=None
TEST=covered by unit test

Review URL: https://codereview.chromium.org/277773002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269660 0039d316-1c4b-4281-b951-d872f2087c98