Remove hard-coded font families in WebUI.

ui/strings/app_locale_settings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/app_locale_settings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="app_locale_settings_am.pak" type="data_package" lang="am" />
     <output filename="app_locale_settings_ar.pak" type="data_package" lang="ar" />
     <if expr="use_third_party_translations">
       <output filename="app_locale_settings_ast.pak" type="data_package" lang="ast" />
@@ skipping 203 matching lines @@
         </message>
         <!-- The relative font size in % used in web-style native pages
         on Windows earlier than Vista (e.g. History).  -->
         <message name="IDS_WEB_FONT_SIZE_XP" use_name_for_id="true">
           75%
         </message>
       </if>
       <if expr="is_macosx">
         <!-- The font used in Web UI (e.g. History). -->
         <message name="IDS_WEB_FONT_FAMILY" use_name_for_id="true">
-          'Lucida Grande', sans-serif
+          'Helvetica Neue', Helvetica, sans-serif

[Dan Beam, 2014/12/10 19:49:25]

I'd separate this

[xdai1, 2014/12/11 02:59:23]

Sorry, I'm not sure about the meaning of "separate this"? 

[Dan Beam, 2014/12/13 02:29:53]

create a new CL with just this one change

         </message>
 
         <!-- The relative font size in % used in Web UI (e.g. History).  -->
         <message name="IDS_WEB_FONT_SIZE" use_name_for_id="true">
           75%
         </message>
       </if>
       <if expr="is_ios">
         <!-- The font used in Web UI (e.g. History). -->
         <message name="IDS_WEB_FONT_FAMILY" use_name_for_id="true">
@@ skipping 30 matching lines @@
         </message>
 
         <!-- The relative font size in % used in Web UI (e.g. History).  -->
         <message name="IDS_WEB_FONT_SIZE" use_name_for_id="true">
           75%
         </message>
       </if>
     </messages>
   </release>
 </grit>