MD Settings: Internet: Convert 'Known Networks' page to dropdown menus

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <message name="IDS_SETTINGS_ABOUT_PAGE_BROWSER_VERSION" desc="The text label describing the version of the browser, example: Version 57.0.2937.0 (Developer Build) unknown (64-bit)">
     Version <ph name="PRODUCT_VERSION">$1<ex>15.0.865.0</ex></ph> (<ph name="PRODUCT_CHANNEL">$2<ex>Developer Build</ex></ph>) <ph name="PRODUCT_MODIFIER">$3</ph> <ph name="PRODUCT_VERSION_BITS">$4</ph>
   </message>
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_DETAILED_BUILD_INFO" desc="Label describing the section that shows detailed information about the current Chrome build.">
       Detailed build information
@@ skipping 1236 matching lines @@
     </message>
     <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_NO_PREFERRED" desc="Entry when there are no preferred networks in the known networks page.">
       None
     </message>
     <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_MESSAGE" desc="Message describing the behavior of the known networks page.">
       Preferred networks will be preferred over other known networks if more than one is available.
     </message>
     <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_ALL" desc="Title for list of all other (non preferred) networks.">
       All networks
     </message>
+    <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_MENU_ADD_PREFERRED" desc="Settings > Internet > Known networks > Dropdown menu item to add a network to the list of preferred networks.">
+      Add to preferred
+    </message>
+    <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_MENU_REMOVE_PREFERRED" desc="Settings > Internet > Known networks > Dropdown menu item to remove a network from the list of preferred networks.">
+      Remove from preferred
+    </message>
+    <message name="IDS_SETTINGS_INTERNET_KNOWN_NETWORKS_MENU_FORGET" desc="Settings > Internet > Known networks > Dropdown menu item to forget a known network.">
+      Forget
+    </message>
 
      <!-- Strings translating ONC (Open Network Configuration) properties -->
      <!-- and translatable values. See onc_spec.html for more information. -->
     <message name="IDS_ONC_IPV4_ADDRESS" desc="ONC Property label for ipv4-IPAddress">
       IP address
     </message>
     <message name="IDS_ONC_IPV4_GATEWAY" desc="ONC Property label for ipv4-Gateway">
       Gateway
     </message>
     <message name="IDS_ONC_IPV4_ROUTING_PREFIX" desc="ONC Property label for ipv4-RoutingPrefix">
@@ skipping 1506 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>