Add empty list indicator for Physical Web WebUI

components/physical_web/webui/resources/physical_web.css

Index: components/physical_web/webui/resources/physical_web.css
diff --git a/components/physical_web/webui/resources/physical_web.css b/components/physical_web/webui/resources/physical_web.css
index 29298209538c5c693104ecb6fa0b2ad1edac560b..0cb4b30e6eb8a2f298bee04e2ddd9396ed5c07cc 100644
--- a/components/physical_web/webui/resources/physical_web.css
+++ b/components/physical_web/webui/resources/physical_web.css
@@ -50,3 +50,7 @@ body {
   overflow: hidden;
   text-overflow: ellipsis;
 }
+
+#empty-list-container {
+  display:none;

[nyquist, 2017/03/02 19:01:27]

Optional nit: Sometimes we write 'display:none' and other times 'display: none'
in our code base. This file in general though seems to prefer the latter. Would
you want to update this to match the style of the rest of the file? Totally up
to you. I won't judge.

[Ran, 2017/03/02 19:36:36]

Done.

+}