Adds the new image for display notifications (2nd)

Previous one was reverted due to failure in Windows; I put the
icon images to cros/ directory but some test code may refer to
that file.

That was actually unexpected, those files are ChromeOS only,
so I excluded the code from non-ChromeOS platforms as r246258.

Now this is safe to reland the same patch.

BUG=254737
TBR=oshima@chromium.org, rouslan@chromium.org

Review URL: https://codereview.chromium.org/145013005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246437 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246437