cros: Use runtime stylus detection for ash palette.

chrome/browser/resources/options/browser_options.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.exportPath('options');
 
 /**
  * @typedef {{actionLinkText: (string|undefined),
  *            accountInfo: (string|undefined),
  *            childUser: (boolean|undefined),
@@ skipping 321 matching lines @@
           $('themes-native-button').disabled = true;
           $('themes-native-button').hidden = true;
         }
         // Supervised users have just one default theme, even on Linux. So use
         // the same button for Linux as for the other platforms.
         $('themes-reset').textContent = loadTimeData.getString('themesReset');
       }
 
       // Device section (ChromeOS only).
       if (cr.isChromeOS) {
-        if (loadTimeData.getBoolean('showStylusSettings')) {
-          $('stylus-settings-link').onclick = function(event) {
-            PageManager.showPageByName('stylus-overlay');
-          };
-          $('stylus-row').hidden = false;
-        }
+        // Probe for stylus hardware state. C++ will invoke
+        // BrowserOptions.setStylusInputStatus_ when the data is available.
+        chrome.send('requestStylusHardwareState');
+
         if (loadTimeData.getBoolean('showPowerStatus')) {
           $('power-settings-link').onclick = function(evt) {
             PageManager.showPageByName('power-overlay');
             chrome.send('coreOptionsUserMetricsAction',
                         ['Options_ShowPowerSettings']);
           };
           $('power-row').hidden = false;
         }
         $('keyboard-settings-button').onclick = function(evt) {
           PageManager.showPageByName('keyboard-overlay');
@@ skipping 1449 matching lines @@
         this.enableElementIfPossible_(
             getRequiredElement('resolve-timezone-by-geolocation'));
         $('timezone-value-select').disabled =
             this.resolveTimezoneByGeolocation_;
         $('resolve-timezone-by-geolocation')
             .checked = this.resolveTimezoneByGeolocation_;
       }
     },
 
     /**
+     * Called when stylus hardware detection probing is complete.
+     * @param {boolean} hasStylus
+     * @private
+     */
+    setStylusInputStatus_: function(hasStylus) {
+      if (!hasStylus)
+        return;
+
+      $('stylus-settings-link').onclick = function(event) {
+        PageManager.showPageByName('stylus-overlay');
+      };
+      $('stylus-row').hidden = false;
+    },
+
+    /**
      * This is called from chromium code when system timezone "managed" state
      * is changed. Enables or disables dependent settings.
      * @param {boolean} managed Is true when system Timezone is managed by
      *     enterprise policy. False otherwize.
      */
     setSystemTimezoneManaged_: function(managed) {
       this.systemTimezoneIsManaged_ = managed;
       this.updateTimezoneSectionState_();
     },
 
@@ skipping 578 matching lines @@
     'setFontSize',
     'setHighContrastCheckboxState',
     'setHotwordRetrainLinkVisible',
     'setMetricsReportingCheckboxState',
     'setMetricsReportingSettingVisibility',
     'setNativeThemeButtonEnabled',
     'setNetworkPredictionValue',
     'setNowSectionVisible',
     'setProfilesInfo',
     'setSpokenFeedbackCheckboxState',
+    'setStylusInputStatus',
     'setSystemTimezoneAutomaticDetectionManaged',
     'setSystemTimezoneManaged',
     'setThemesResetButtonEnabled',
     'setVirtualKeyboardCheckboxState',
     'setWallpaperManaged',
     'setupPageZoomSelector',
     'setupProxySettingsButton',
     'showCreateProfileError',
     'showCreateProfileSuccess',
     'showCreateProfileWarning',
@@ skipping 46 matching lines @@
 
       settings.hidden = !isVisible;
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });