Update some webui question mark icons to SVG.

ui/webui/resources/webui_resources.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This comment is only here because changes to resources are not picked up
 without changes to the corresponding grd file. -->
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/webui_resources.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="grit/webui_resources_map.cc"
             type="resource_file_map_source" />
@@ skipping 171 matching lines @@
       <include name="IDR_WEBUI_IMAGES_CHECKBOX_WHITE"
                file="images/checkbox_white.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_DISABLED_SELECT"
                file="images/disabled_select.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_ERROR"
                file="images/error.svg" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_GEAR"
                file="images/gear.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_GOOGLE_TRANSPARENT"
                file="images/google-transparent.png" type="BINDATA" />
-      <include name="IDR_WEBUI_IMAGES_HELP"
-               file="images/help.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_QUESTION_MARK"
                file="images/question_mark.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_SELECT"
                file="images/select.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_THROBBER"
                file="images/throbber.svg" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_TRASH"
                file="images/trash.png" type="BINDATA" />
       <include name="IDR_WEBUI_IMAGES_CLOUDS"
                file="images/clouds.png" type="BINDATA" />
@@ skipping 239 matching lines @@
                    type="chrome_html" />
         <structure name="IDR_WEBUI_JS_UI_ACCOUNT_TWEAKS"
                    file="js/chromeos/ui_account_tweaks.js"
                    type="chrome_html" />
       </if>
       <part file="cr_elements_resources.grdp" />
       <part file="polymer_resources.grdp" />
     </structures>
   </release>
 </grit>