Disable wallpaper button in Guest mode settings

chrome/browser/resources/options/browser_options.js

Index: chrome/browser/resources/options/browser_options.js
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index 1bc711f8e33eaccc7c1fde4d77f5493a1b866c1f..abc7b22a7ec6e956ec06bb91196b4b4f3d1230aa 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -1493,7 +1493,7 @@ cr.define('options', function() {
      */
     setWallpaperManaged_: function(managed) {
       var button = $('set-wallpaper');
-      button.disabled = !!managed;
+      button.disabled |= !!managed;

[stevenjb, 2014/09/24 16:15:23]

nit: Actually, I think that in general this kind of thing is more clear as:
if (managed)
  button.disabled = true;
But that is really just a personal preference.

[michaelpg, 2014/09/24 22:29:23]

+dbeam@

Actually it looks like this can be called again, if the policy changes after the
page has loaded. We shouldn't enable the button if it's already been disabled by
UIAccountTweaks. I've added a helper function there I'd like Dan to take a look
at. I think some other controls should migrate to that function, too.

[Dan Beam, 2014/09/29 18:52:18]

why are we doing !! if |managed| should already be a boolean?

[Dan Beam, 2014/09/29 18:52:18]

any version including:

  button.disabled = button.disabled || managed;

is fine by me.  no particular preference here.  i'd say out of all the versions,
stevenjb@'s is probably the easiest to read, but we do (in general) prefer to
hit the same codepaths when possible (e.g. instead of if/else => ternary).

 
       // Create a synthetic pref change event decorated as
       // CoreOptionsHandler::CreateValueForPref() does.