Add empty list indicator for Physical Web WebUI

components/physical_web/webui/resources/physical_web.html

Index: components/physical_web/webui/resources/physical_web.html
diff --git a/components/physical_web/webui/resources/physical_web.html b/components/physical_web/webui/resources/physical_web.html
index a5a0ba698842d76e0b2decc0c2242c55fcc6c695..83ffd8ba6d5b818efea54e3195ea1e6075a87e95 100644
--- a/components/physical_web/webui/resources/physical_web.html
+++ b/components/physical_web/webui/resources/physical_web.html
@@ -38,6 +38,12 @@
 
 </div>
 
+<div id="empty-container" i18n-content="emptyMessage" style="visibility:hidden">

[cco3, 2017/02/23 20:07:31]

Is there a reason we should do visibility:hidden instead of display:none?  Same
with below for display:block

Also, I think the css should be in physical_web.css

[Ran, 2017/02/23 20:59:45]

Moved css to physical_web.css.
For visibility over display, I was referring the "body-container" and try to
make it consistent.

+</div>
+
+<div id="scan-container" i18n-content="scanningMessage" style="visibility:visible">
+</div>
+
 <script src="chrome://resources/js/i18n_template.js"></script>
 <script src="chrome://resources/js/jstemplate_compiled.js"></script>
 </body>