Move some Physical Web strings to new location and add OWNERS

components/physical_web_ui_strings.grdp

Index: components/physical_web_ui_strings.grdp
diff --git a/components/physical_web_ui_strings.grdp b/components/physical_web_ui_strings.grdp
index cc34d512cc4c9c1533651fe315778ac1407ce739..e89251584e21c4c45ebba4fb161eb719f549cb41 100644
--- a/components/physical_web_ui_strings.grdp
+++ b/components/physical_web_ui_strings.grdp
@@ -3,4 +3,10 @@
   <message name="IDS_PHYSICAL_WEB_UI_TITLE" desc="Title of a built-in page that displays a list of Physical Web URLs (URLs broadcast by nearby devices).">
     Physical Web
   </message>
+  <message name="IDS_PHYSICAL_WEB_UI_EMPTY_MESSAGE" desc="The message displayed in place of a list of nearby URLs when there are no URLs to display.">

[cco3, 2017/02/16 22:34:43]

Why are we adding strings if we aren't using them?

[Ran, 2017/02/16 22:48:32]

I have another cl that uses this string.
https://codereview.chromium.org/2698503004/

I try to catch the feature freeze deadline, as strings require translation need
to go before it...

+    No Physical Web URLs to show

[cco3, 2017/02/16 22:34:43]

Haven't we avoided using the term "URL"?  This should be No Physical Web pages

[Ran, 2017/02/16 22:48:32]

Done. Thanks!

+  </message>
+  <message name="IDS_PHYSICAL_WEB_UI_SCANNING_MESSAGE" desc="The message displayed in place of a list of nearby URLs while still scanning for nearby URLs.">
+    Looking for nearby Physical Web pages
+  </message>
 </grit-part>