chromium-assets: Update boot splash images.

This looks pretty similar to what we use for official
builds.  (The font isn't exactly correct, but Nimbus Sans
Condensed was both close and already installed on my Ubuntu
system.)

Change-Id: Ic743163450c22556e51666daecb218a211bb2923

BUG=chromium-os:10292
TEST=put them on a system and booted it

Review URL: http://codereview.chromium.org/5981002
6 files changed
tree: 3f907dbf0ac074e676c15befc47ce2b913397938
  1. README
  2. images/
  3. inherit-review-settings-ok
  4. screensavers/