Migrate WebKit "global script" font prefs.

chrome/browser/resources/options2/font_settings.html

 <div id="font-settings" class="page" hidden>
   <div class="close-button"></div>
   <h1 i18n-content="fontSettingsPage"></h1>
   <div class="content-area">
     <section>
       <h3 i18n-content="fontSettingsStandard"></h3>
       <div class="font-setting-container">
         <div class="font-input-div">
           <div>
             <select id="standard-font-family" class="font-input"
                 data-type="string" metric="Options_ChangeStandardFont"
-                pref="webkit.webprefs.global.standard_font_family">
+                pref="webkit.webprefs.fonts.standard.Zyyy">
             </select>
           </div>
           <div>
             <input id="standard-font-size" type="range" min="0" max="24"
                 pref="webkit.webprefs.global.default_font_size">
             <div>
               <span i18n-content="fontSettingsSizeTiny"></span>
               <span i18n-content="fontSettingsSizeHuge"
                   class="font-settings-huge">
               </span>
             </div>
           </div>
         </div>
         <div id="standard-font-sample" class="font-sample-div"></div>
       </div>
     </section>
     <section>
       <h3 i18n-content="fontSettingsSerif"></h3>
       <div class="font-setting-container">
         <div class="font-input-div">
           <div>
             <select id="serif-font-family" class="font-input" data-type="string"
-                pref="webkit.webprefs.global.serif_font_family"
+                pref="webkit.webprefs.fonts.serif.Zyyy"
                 metric="Options_ChangeSerifFont">
             </select>
           </div>
         </div>
         <div id="serif-font-sample" class="font-sample-div"></div>
       </div>
     </section>
     <section>
       <h3 i18n-content="fontSettingsSansSerif"></h3>
       <div class="font-setting-container">
         <div class="font-input-div">
           <div>
             <select id="sans-serif-font-family" class="font-input"
                 data-type="string" metric="Options_ChangeSansSerifFont"
-                pref="webkit.webprefs.global.sansserif_font_family">
+                pref="webkit.webprefs.fonts.sansserif.Zyyy">
             </select>
           </div>
         </div>
         <div id="sans-serif-font-sample" class="font-sample-div"></div>
       </div>
     </section>
     <section>
       <h3 i18n-content="fontSettingsFixedWidth"></h3>
       <div class="font-setting-container">
         <div class="font-input-div">
           <div>
             <select id="fixed-font-family" class="font-input" data-type="string"
-                pref="webkit.webprefs.global.fixed_font_family"
+                pref="webkit.webprefs.fonts.fixed.Zyyy"
                 metric="Options_ChangeFixedFont">
             </select>
           </div>
         </div>
         <div id="fixed-font-sample" class="font-sample-div"></div>
       </div>
     </section>
     <section>
       <h3 i18n-content="fontSettingsMinimumSize"></h3>
       <div class="font-setting-container">
@@ skipping 23 matching lines @@
         </div>
       </div>
     </section>
   </div>
   <div class="action-area">
     <div class="button-strip">
       <button id="font-settings-confirm" i18n-content="ok"></button>
     </div>
   </div>
 </div>