[CUPS] Put the CUPS settings UI behind a command line flag --enable-native-cups.

chrome/browser/resources/settings/printing_page/printing_page.html

Index: chrome/browser/resources/settings/printing_page/printing_page.html
diff --git a/chrome/browser/resources/settings/printing_page/printing_page.html b/chrome/browser/resources/settings/printing_page/printing_page.html
index ba31ae302b678bc1da7520995ccfab75d555ab0b..3b182eb9850667df77913c391732e2b6cba7bf51 100644
--- a/chrome/browser/resources/settings/printing_page/printing_page.html
+++ b/chrome/browser/resources/settings/printing_page/printing_page.html
@@ -21,11 +21,13 @@
       </array-selector>
       <neon-animatable route-path="default">
 <if expr="chromeos">
-        <div id="cupsPrinters" class="settings-box first"
-            on-tap="onTapCupsPrinters_" actionable>
-          <iron-icon icon="cr:print"></iron-icon>
-          <div class="middle">$i18n{cupsPrintersTitle}</div>
-        </div>
+        <template is="dom-if" if="[[showCupsPrintingFeatures_]]">
+          <div id="cupsPrinters" class="settings-box first"
+              on-tap="onTapCupsPrinters_" actionable>
+            <iron-icon icon="cr:print"></iron-icon>
+            <div class="middle">$i18n{cupsPrintersTitle}</div>
+          </div>
+        </template>
 </if>
         <div id="cloudPrinters" class="settings-box"
             on-tap="onTapCloudPrinters_" actionable>