Introduce settings-related data attribute

chrome/settings.html

@@ -27,7 +27,7 @@
 
             <div class="settings-item slider">
 
-                <input class="slider-input" type="range" max="2" value="0" id="slider-input">
+                <input class="slider-input" type="range" max="2" value="0" data-setting-id="security_level">
 
                 <div class="slider-legend">
                     <div class="slider-legend-item text-left" data-l10n-id="standard_label"></div>
@@ -37,7 +37,7 @@
 
             </div>
 
-            <div class="settings-item notice">
+            <div class="settings-item notice" data-hidden="false">
 
                 <div class="notice-body">
                     <div data-l10n-id="standard_description"></div>
@@ -45,7 +45,7 @@
 
             </div>
 
-            <div class="settings-item notice">
+            <div class="settings-item notice" data-hidden="true">
 
                 <div class="notice-body">
 
@@ -62,7 +62,7 @@
 
             </div>
 
-            <div class="settings-item notice">
+            <div class="settings-item notice" data-hidden="true">
 
                 <div class="notice-body">