Add custom Polymer network icon element

ui/webui/resources/webui_resources.grd

Index: ui/webui/resources/webui_resources.grd
diff --git a/ui/webui/resources/webui_resources.grd b/ui/webui/resources/webui_resources.grd
index f44246fdaff604a1c8185f22fa03464a0e8b862d..3f9b6adc39abb37037aff6b22744350935bccfb9 100644
--- a/ui/webui/resources/webui_resources.grd
+++ b/ui/webui/resources/webui_resources.grd
@@ -202,6 +202,8 @@ without changes to the corresponding grd file. -->
                file="images/trash.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_CLOUDS"
                file="images/clouds.png" type="BINDATA" />
+
+      <part file="cr_elements_images.grdp" />
     </includes>
     <structures>
       <structure name="IDR_WEBUI_CSS_ALERT_OVERLAY"
@@ -376,8 +378,6 @@ without changes to the corresponding grd file. -->
                  file="js/parse_html_subset.js" type="chrome_html" />
       <structure name="IDR_WEBUI_JS_UTIL"
                  file="js/util.js" type="chrome_html" flattenhtml="true" />
-      <structure name="IDR_WEBUI_JS_WEBUI_RESOURCE_TEST"
-                 file="js/webui_resource_test.js" type="chrome_html" />
       <if expr="chromeos">
         <structure name="IDR_WEBUI_CSS_UI_ACCOUNT_TWEAKS"
                    file="css/chromeos/ui_account_tweaks.css"