chromeos: Improve version label on login screen.

This changes the color of the version label on the login
screen (shown only for dev builds, I believe) so it uses
light text with a dark outline instead of light-gray text
with a white shadow, which just looks blurry to me.

BUG=139360
TEST=version text is more readable with light and dark backgrounds

Review URL: https://chromiumcodereview.appspot.com/10837263

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@152382 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/chromeos/login/oobe.css

@@ -1283,12 +1283,14 @@ html[dir=rtl] .error-message {
 
 #version-labels {
   -webkit-transition: all 500ms linear;
-  color: #999;
+  color: #fff;
   font-size: 11px;
   margin: 10px;
-  opacity: 1.0;
   text-align: end;
-  text-shadow: 0 1px 1px #fff;
+  text-shadow:
+      0 0 4px rgba(0,0,0,.6),
+      0 1px 2px rgba(0,0,0,.8),
+      0 -1px 2px rgba(0,0,0,1);
 }
 
 #offline-network-control {