Add settings for keyboard auto-repeat to options page.

chrome/browser/resources/options/pref_ui.js

Index: chrome/browser/resources/options/pref_ui.js
diff --git a/chrome/browser/resources/options/pref_ui.js b/chrome/browser/resources/options/pref_ui.js
index b4f28308bf885b9861983cdab305ba4e19f358f6..2e375001688bd064f8338b25258a18aa581e1957 100644
--- a/chrome/browser/resources/options/pref_ui.js
+++ b/chrome/browser/resources/options/pref_ui.js
@@ -81,12 +81,14 @@ cr.define('options', function() {
     },
 
     /**
-     * Update the input element's state when the associated pref changes.
+     * Handles changes to the pref. If a custom change handler does not suppress
+     * it, a default handler is invoked that update the input element's state.
      * @param {Event} event Pref change event.
      * @private
      */
     updateStateFromPref_: function(event) {
-      this.value = event.value.value;
+      if (!this.customPrefChangeHandler(event))
+        this.value = event.value.value;
     },
 
     /**
@@ -107,6 +109,17 @@ cr.define('options', function() {
     customChangeHandler: function(event) {
       return false;
     },
+
+    /**
+     * Custom change handler that is invoked first when the preference
+     * associated with the input element changes. If it returns false, a default
+     * handler is invoked next that updates the input element. If it returns
+     * true, the default handler is suppressed.
+     * @param {Event} event Input element change event.
+     */
+    customPrefChangeHandler: function(event) {
+      return false;
+    },
   };
 
   /**
@@ -184,8 +197,10 @@ cr.define('options', function() {
      * @private
      */
     updateStateFromPref_: function(event) {
-      var value = Boolean(event.value.value);
-      this.checked = this.inverted_pref ? !value : value;
+      if (!this.customPrefChangeHandler(event)) {

[stevenjb, 2014/07/22 16:42:23]

nit: Here and below, I think the logic would be a tiny bit more clear using an
early exit.

[michaelpg, 2014/07/22 17:34:54]

Done.

+        var value = Boolean(event.value.value);
+        this.checked = this.inverted_pref ? !value : value;
+      }
     },
   };
 
@@ -264,7 +279,8 @@ cr.define('options', function() {
      * @private
      */
     updateStateFromPref_: function(event) {
-      this.checked = this.value == String(event.value.value);
+      if (!this.customPrefChangeHandler(event))
+        this.checked = this.value == String(event.value.value);
     },
   };
 
@@ -328,13 +344,17 @@ cr.define('options', function() {
     },
 
     /**
-     * Update the slider position when the associated pref changes.
+     * Handles changes to the pref associated with the slider. If a custom
+     * change handler does not suppress it, a default handler is invoked that
+     * updates the slider position.
      * @param {Event} event Pref change event.
      * @private
      */
     updateStateFromPref_: function(event) {
-      var value = event.value.value;
-      this.value = this.valueMap ? this.valueMap.indexOf(value) : value;
+      if (!this.customPrefChangeHandler(event)) {
+        var value = event.value.value;
+        this.value = this.valueMap ? this.valueMap.indexOf(value) : value;
+      }
     },
 
     /**
@@ -392,6 +412,9 @@ cr.define('options', function() {
      * @private
      */
     updateStateFromPref_: function(event) {
+      if (this.customPrefChangeHandler(event))
+        return;
+
       // Make sure the value is a string, because the value is stored as a
       // string in the HTMLOptionElement.
       value = String(event.value.value);